Skype

The name for the software is derived from "Sky peer-to-peer", which was then abbreviated to "Skyper". However, some of the domain names associated with "Skyper" were already taken.[13] Dropping the final "r" left the current title "Skype", for which domain names were available.[14]

Skype was founded in 2003 by Niklas Zennström, from Sweden, and Janus Friis, from Denmark.[15] The Skype software was created by Estonians Ahti Heinla, Priit Kasesalu, Jaan Tallinn, and Toivo Annus.[16] Friis and Annus are credited with the idea of reducing the cost of voice calls by using a P2P protocol like that of Kazaa.[17] An early alpha version was created and tested in spring 2003, and the first public beta version was released on 29 August 2003.[18][17]

In June 2005, Skype entered an agreement with the Polish web portal Onet.pl for an integrated offering on the Polish market.[19] On 12 September 2005, eBay Inc. agreed to acquire Luxembourg-based Skype Technologies SA for approximately US$2.5 billion in up-front cash and eBay stock, plus potential performance-based consideration.[20] On 1 September 2009, eBay announced it was selling 65% of Skype to Silver Lake, Andreessen Horowitz, and the Canada Pension Plan Investment Board for US$1.9 billion, valuing Skype at US$2.75 billion.[21] On 14 July 2011, Skype partnered with Comcast to bring its video chat service to Comcast subscribers via HDTV sets.[22]

On 17 June 2013, Skype released a free video messaging service, which can be operated on Windows, Mac OS, iOS, iPadOS, Android, and BlackBerry.[23]

Between 2017 and 2020, Skype collaborated with PayPal to provide a money-send feature. It allowed users to transfer funds via the Skype mobile app in the middle of a conversation.[24]

In 2019, Skype was announced to be the sixth most downloaded mobile app of the decade, from 2010 to 2019.[25]

Microsoft acquisition

Skype icon, 2006–2012

Skype icon, 2012–2019

Skype icon, 2019–present

On 10 May 2011, Microsoft Corporation acquired Skype Communications, S.à r.l for US$8.5 billion.[26] The company was incorporated as a division of Microsoft, which acquired all its technologies with the purchase. The acquisition was completed on 13 October 2011.[26][27] Shortly after the acquisition, Microsoft began integrating the Skype service with its own products. Along with taking over the development of existing Skype desktop and mobile apps, the company developed a dedicated client app for its then-newly released, touch-focused Windows 8 and Windows RT operating systems. They were made available from Windows Store when the then-new OS launched on 26 October 2012. The following year, it became the default messaging app for Windows 8.1, replacing the Windows 8 Messaging app at the time, and became pre-installed software on every device that came with or upgraded to 8.1.[28]

In a month-long transition from 8 to 30 April 2013, Microsoft discontinued two of its own products in favor of Skype, including its Windows Live Messenger instant messaging service, although Messenger continued to be available in mainland China until October 2014.[29][30]

On 11 November 2014, Microsoft announced that in 2015, its Lync product would be replaced by Skype for Business. This combined features of Lync and the consumer Skype software. There are two user interfaces, organizations could switch their users between the default Skype for Business interface to the Lync interface.[31]

Registered users of Skype are identified by a unique Skype ID and may be listed in the Skype directory under a Skype username.[52] Skype allows these registered users to communicate through both instant messaging and voice chat. Voice chat allows telephone calls between pairs of users and conference calling and uses proprietary audio codec. Skype's text chat client allows group chats, emoticons, storing chat history, and editing of previous messages. Offline messages were implemented in a beta build of version 5 but removed after a few weeks without notification. The usual features familiar to instant messaging users—user profiles, online status indicators, and so on—are also included.

The Online Number, a.k.a. SkypeIn, service allows Skype users to receive calls on their computers dialed by conventional phone subscribers to a local Skype phone number; local numbers are available for Australia, Belgium, Brazil, Chile, Colombia, Denmark, the Dominican Republic, Estonia, Finland, France, Germany, Hong Kong, Hungary, India, Ireland, Japan, Mexico, Nepal, New Zealand, Poland, Romania, South Africa, South Korea, Sweden, Switzerland, Turkey, the Netherlands, the United Kingdom, and the United States.[53][54] A Skype user can have local numbers in any of these countries, with calls to the number charged at the same rate as calls to fixed lines in the country.

Skype supports conference calls, video chats, and screen sharing between 25 people at a time for free,[55] which then increased to 50 on 5 April 2019.[56]

Skype does not provide the ability to call emergency numbers, such as 112 in Europe, 911 in North America, 999 in the UK or 100 in India and Nepal.[57] However, as of December 2012, there is limited support for emergency calls in the United Kingdom, Australia, Denmark, and Finland.[58] The U.S. Federal Communications Commission (FCC) has ruled that, for the purposes of section 255 of the Telecommunications Act, Skype is not an "interconnected VoIP provider".[59] As a result, the U.S. National Emergency Number Association recommends that all VoIP users have an analog line available as a backup.[60]

In 2019, Skype added an option to blur the background in a video chat interface using AI algorithms purely done using software, despite a depth-sensing camera not being present in most webcams.[61]

In 2023, Skype added the Bing AI chatbot to the platform for users who had access to the chatbot.[62]

At the end of 2010, there were over 660 million worldwide users, with over 300 million estimated active each month as of August 2015.[80] At one point in February 2012, there were 34 million users concurrently online on Skype.[81]

In January 2011, after the release of video calling on the Skype client for iPhone, Skype reached a record 27 million simultaneous online users.[82] This record was broken with 29 million simultaneous online users on 21 February 2011[83] and again on 28 March 2011 with 30 million online users.[84] On 25 February 2012, Skype announced that it has over 32 million users for the first time ever.[85] By 5 March 2012, it had 36 million simultaneous online users,[86] and less than a year later, on 21 January 2013, Skype had more than 50 million concurrent users online.[87] In June 2012, Skype had surpassed 70 million downloads on Android.[88]

On 19 July 2012, Microsoft announced that Skype users had logged 115 billion minutes of calls in the quarter, up to 50% since the last quarter.[89]

On 15 January 2014, TeleGeography estimated that Skype-to-Skype international traffic has gone up to 36% in 2013 to 214 billion minutes.[90]

As of March 2020, Skype was used by 100 million people at least once a month and by 40 million people each day.[91]

At end March 2020 there was a 70% increase in the number of daily users from the previous month, due to the COVID-19 pandemic.[92] However Skype also lost a large part of its market share to Zoom.[93]

Skype was claimed initially to be a secure communication, with one of its early web pages stating "highly secure with end-to-end encryption".[129] Security services were invisible to the user, and encryption cannot be disabled. Skype claims to use publicly documented, widely trusted encryption techniques for Skype-to-Skype communication: RSA for key negotiation and the Advanced Encryption Standard to encrypt conversations.[130] However, it is impossible to verify that these algorithms are used correctly, completely, and at all times, as there is no public review possible without a protocol specification and/or the program's source code. Skype provides an uncontrolled registration system for users with no proof of identity. Instead, users may choose a screen name which does not have to relate to their real-life identity in any way; a name chosen could also be an impersonation attempt, where the user claims to be someone else for fraudulent purposes. A third-party paper analyzing the security and methodology of Skype was presented at Black Hat Europe 2006. It analyzed Skype and found a number of security issues with the then-current security model.[131]

PRISM: a clandestine surveillance program under which the NSA collects user data from companies like Skype and Facebook[132]

Skype incorporates some features that tend to hide its traffic, but it is not specifically designed to thwart traffic analysis and therefore does not provide anonymous communication. Some researchers have been able to watermark the traffic so that it is identifiable even after passing through an anonymizing network.[133]

In an interview, Kurt Sauer, the Chief Security Officer of Skype, said, "We provide a safe communication option. I will not tell you whether we can listen or not."[134] This does not deny the fact that the U.S. National Security Agency (NSA) monitors Skype conversations. Skype's client uses an undocumented and proprietary protocol. The Free Software Foundation (FSF) is concerned about user privacy issues arising from using proprietary software and protocols and has made a replacement for Skype one of their high-priority projects.[135] Security researchers Biondi and Desclaux have speculated that Skype may have a back door, since Skype sends traffic even when it is turned off and because Skype has taken extreme measures to obfuscate the program's traffic and functioning.[136] Several media sources reported that at a meeting about the "Lawful interception of IP based services" held on 25 June 2008, high-ranking unnamed officials at the Austrian interior ministry said that they could listen in on Skype conversations without problems. Austrian public broadcasting service ORF, citing minutes from the meeting, reported that "the Austrian police are able to listen in on Skype connections". Skype declined to comment on the reports.[137][138] One easily demonstrated method of monitoring is to set up two computers with the same Skype user ID and password. When a message is typed or a call is received on one computer, the second computer duplicates the audio and text. This requires knowledge of the user ID and password.

The United States Federal Communications Commission (FCC) has interpreted the Communications Assistance for Law Enforcement Act (CALEA) as requiring digital phone networks to allow wiretapping if authorized by an FBI warrant, in the same way as other phone services. In February 2009, Skype said that, not being a telephone company owning phone lines, it is exempt from CALEA and similar laws, which regulate US phone companies, and it is not clear whether Skype could support wiretapping even if it wanted to.[139] According to the ACLU, the Act is inconsistent with the original intent of the Fourth Amendment to the U.S. Constitution;[140] more recently, the ACLU has expressed the concern that the FCC interpretation of the Act is incorrect.[141][142] It has been suggested that Microsoft made changes to Skype's infrastructure to ease various wiretapping requirements;[143] however, Skype denies the claims.[144]

Sometime before Skype was sold in 2009, the company had started Project Chess, a program to explore legal and technical ways to easily share calls with intelligence agencies and law enforcement.[145]

On 20 February 2009, the European Union's Eurojust agency announced that the Italian Desk at Eurojust would "play a key role in the coordination and cooperation of the investigations on the use of internet telephony systems (VoIP), such as 'Skype'. [...] The purpose of Eurojust's coordination role is to overcome the technical and judicial obstacles to the interception of internet telephony systems, taking into account the various data protection rules and civil rights."[146]

In November 2010, a flaw was disclosed to Skype that showed how computer crackers could secretly track any user's IP address.[147] Due to Skype's peer-to-peer nature, this was a difficult issue to address, but this bug was eventually remedied in a 2016 update.[148]

In 2012, Skype introduced automatic updates to better protect users from security risks but received some challenge from users of the Mac product, as the updates cannot be disabled from version 5.6 on,[149] both on Mac OS and Windows versions, although in the latter, and only from version 5.9 on, automatic updating can be turned off in certain cases.[150]

According to a 2012 Washington Post article, Skype "has expanded its cooperation with law enforcement authorities to make online chats and other user information available to police"; the article additionally mentions Skype made changes to allow authorities access to addresses and credit card numbers.[151]

In November 2012, Skype was reported to have handed over user data of a pro-WikiLeaks activist to Dallas, Texas-based private security company iSIGHT Partners without a warrant or court order. The alleged handover would be a breach of Skype's privacy policy. Skype responded with a statement that it launched an internal investigation to probe the breach of user data privacy.[152]

On 13 November 2012, a Russian user published a flaw in Skype's security, which allowed any person to take over a Skype account knowing only the victim's email by following seven steps.[153][154] This vulnerability was claimed to exist for months and existed for more than 12 hours since published widely.

On 14 May 2013, it was documented that a URL sent via a Skype instant messaging session was usurped by the Skype service and subsequently used in a HTTP HEAD query originating from an IP address registered to Microsoft in Redmond (the IP address used was 65.52.100.214). The Microsoft query used the full URL supplied in the IM conversation and was generated by a previously undocumented security service.[155] Security experts speculate the action was triggered by a technology similar to Microsoft's SmartScreen Filter used in its browsers.[156]

The 2013 mass surveillance disclosures revealed that agencies such as the NSA and the FBI have the ability to eavesdrop on Skype, including the monitoring and storage of text and video calls and file transfers.[157][158][159] The PRISM surveillance program, which requires FISA court authorization, reportedly has allowed the NSA unfettered access to its data center supernodes. According to the leaked documents, integration work began in November 2010, but it was not until February 2011 that the company was served with a directive to comply signed by the attorney general,[157] with NSA documents showing that collection began on 31 March 2011.[160]

On 10 November 2014, Skype scored 1 out of 7 points on the Electronic Frontier Foundation's secure messaging scorecard. Skype received a point for encryption during transit but lost points because communications are not encrypted with a key the provider does not have access to (i.e. the communications are not end-to-end encrypted), users cannot verify contacts' identities, past messages are not secure if the encryption keys are stolen (i.e. the service does not provide forward secrecy), the code is not open to independent review (i.e. not available to merely view, nor under a free-software license), the security design is not properly documented, and there has not been a recent independent security audit.[161][162][163] AIM, BlackBerry Messenger, Ebuddy XMS, Hushmail, Kik Messenger, Viber and Yahoo Messenger also scored 1 out of 7 points.[161]

As of August 2018, Skype now supports end-to-end encryption across all platforms.[164]

Skype comes bundled with the following locales and languages: Arabic, Bulgarian, Catalan, Chinese (Traditional and Simplified), Croatian, Czech, Danish, Dutch, English, Estonian, Finnish, French, German, Greek, Hebrew, Hungarian, Indonesian, Italian, Japanese, Korean, Latvian, Lithuanian, Nepali, Norwegian, Polish, Portuguese (Brazilian and European), Romanian, Russian, Serbian, Slovak, Slovenian, Spanish, Swedish, Thai, Turkish, Ukrainian, and Vietnamese.

As the Windows desktop program offers users the option of creating new language files, at least 80 other (full or partial) localizations are also available for many languages.[179]

In January 2010, Skype rescinded its policy of seizing funds in Skype accounts that have been inactive (no paid call) for 180 days. This was in settlement of a class-action lawsuit.[180] Skype also paid up to US$4 to persons who opted into the action.

As of February 2012, Skype provides support through their web support portal, support community, @skypesupport on Twitter, and Skype Facebook page. Direct contact via email and live chat is available through their web support portal. Chat Support is a premium feature available to Skype Premium and some other paid users.

Skype's refund policy states that they will provide refunds in full if customers have used less than 1 euro of their Skype Credit. "Upon a duly submitted request, Skype will refund you on a pro-rata basis for the unused period of a Product".

Skype has come under some criticism from users for the inability to completely close accounts. Users not wanting to continue using Skype can make their account inactive by deleting all personal information, except for the username.[181]

Due to an outage on 21 September 2015 that affected several users in New Zealand, Australia, and other countries, Skype decided to compensate their customers with 20 minutes of free calls to over 60 landline and 8 mobile phone destinations.[182]

Although Skype is a commercial product, its non-paid version is used with increasing frequency among teachers, schools, and charities interested in global education projects.[183] A popular use case is to facilitate language learning through conversations that alternate between each participant's native language.[184][185][186][187]

The video conferencing aspect of the software has been praised for its ability to connect students who speak different languages, facilitate virtual field trips, and engage directly with experts.[188][189]

Skype in the classroom is another free-of-charge tool that Skype has set up on its website, designed to encourage teachers to make their classrooms more interactive, and collaborate with other teachers around the world. There are various Skype lessons in which students can participate. Teachers can also use a search tool and find experts in a particular field.[190] The educational program Skype a Scientist, set up by biologist Sarah McAnulty in 2017, had in two years connected 14,312 classrooms with over 7000 volunteer scientists.[191]

However, Skype is not adopted universally, with many educational institutions in the United States and Europe blocking the application from their networks.

• Caller ID spoofing
• Censorship of Skype
• Comparison of cross-platform instant messaging clients
• Comparison of instant messaging protocols
• Comparison of VoIP software
• List of video telecommunication services and product brands
• Mobile VoIP
• Presence information
• Unified communications

• Official website