Odnoklassniki

Odnoklassniki (Russian: Одноклассники, lit. 'Classmates'code: rus promoted to code: ru ), abbreviated as OK or OK.ru, is a social networking service and online video sharing website primarily in Russia and former Soviet Republics. The site was launched on March 4, 2006, by Albert Popkov and is currently owned by VK.

The website currently has more than 200 million registered users and 45 million daily unique visitors. Odnoklassniki also currently has an Alexa Internet traffic ranking of 56 worldwide and 7 for Russia. Odnoklassniki is the second most popular social network in Russia, behind VK (VKontakte) but ahead of Facebook, which is in 3rd place.

Odnoklassniki was launched on March 26, 2006, by Albert Popkov, a telecommunications professional residing in London. Having previously been involved in similar projects in other European countries, Popkov initially developed Odnoklassniki as a hobby project from March to November 2006. During this period, it was only mentioned commercially within a friendly advertising agency as an advertising platform.

However, due to a significant increase in userbase, Popkov established a separate legal entity for the service. By July 2007, Odnoklassniki had grown its audience to 3 million users. In November 2009, the British company I-CD accused Popkov of copyright infringement, alleging that he used proprietary information to create a site similar to I-CD's social network Passado. Popkov was previously employed by I-CD but had resigned in November 2005. Popkov denied these allegations, but was eventually dismissed as managing director of Odnoklassniki. In November 2009, after the first day of trial in the Royal Courts of Justice, I-CD dropped all charges against Popkov and Odnoklassniki after they agreed to pay an undisclosed amount as settlement.

In September 2008, Popkov sold a controlling interest in Odnoklassniki to Digital Sky Technologies (DST), the owner of Mail.ru. DST and its subsidiary, Forticom, acquired a 58% stake in the network. Paid registration was introduced in Odnoklassniki in 2008, but this led to a decline in popularity as users began migrating to the main competitor, VKontakte. As a result, Odnoklassniki reverted to a free model and discontinued user registration fees by August 2010.

On January 23, 2009, a service was launched which allows a user to clear their personal page of uninvited guests by removing them from the list of views as well as allowing the blocking access from all users that they are not "friends" with on the service.

In early April 2010 beta testing games became available on the site, developed by i-Jet, and on December 24, 2010, users of Odnoklassniki publicly released a beta version of video chat. Regular updates between 2011 and 2019 saw additional features added, such as the ability to divide friends into groups, a music section where users could upload MP3 files, and detailed customizable user themes. Odnoklassniki reached 40 million users per day in 2013 and in 2022, following the block of Instagram by Roskomnadzor, about 4% of the former Instagram users polled by Zarplata.ru said they had switched to Odnoklassniki.

Additionally, Odnoklassniki introduced advertising formats, launched its messenger called OK Messages, included live broadcasts in communities, and developed a video app called OK Video for Smart TV. The social network also faced challenges, such as being blocked by the Ukrainian government in retaliation for the annexation of Crimea and dealing with technical issues that temporarily affected site availability.^{[citation needed]}