Odnoklassniki

Odnoklassniki (, ) is a social network service used mainly in Russia and former Soviet Republics. The site was developed by Albert Popkov and launched on March 4, 2006.
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.
History.
The Odnoklassniki project was launched on March 26, 2006.
The creator of the site, Albert Popkov, who lives in London and works in the field of telecommunications, took part in the creation of similar projects in other European countries. From March to November 2006, the project existed as a hobby and was commercially mentioned only in a friendly advertising agency as a platform for advertising. The number of users who registered on the site grew exponentially, so the founder of the project decided to create a separate legal entity.
By July 2007, the social network Odnoklassniki has increased its audience to 4 million users.
In February 2008, British company I-CD accused Popkov of violating their copyright. According to I-CD, Albert Popkov as an employee of I-CD worked on their projects 192.com and Passado until his resignation in November 2005. In December 2006 the company raised €10 million to expand Passado in Russia. Albert Popkov allegedly used the proprietary information to create his own site very similar to Passado. He denied those allegations, but was later dismissed as Managing Director by Odnoklassniki. in November 2009, after the first day of trial in the Royal Courts of Justice, I-CD dropped all charges against Albert Popkov and Odnoklassniki after Albert Popkov and Odnoklassniki agreed to pay i-CD an undisclosed amount in settlement.
On September 15, 2008, "Vedomosti" reported that Popkov had sold a controlling interest in the network to Digital Sky Technologies (DST), the owner of Mail.ru. DST and its subsidiary Forticom together control 58% of the network. On the previous day it was announced during a news conference that the network's interface would be translated into Azerbaijani.
Paid registration was introduced in Odnoklassniki in 2008.
In July 2009, Odnoklassniki social network ranked fifth in terms of monthly reach for an audience of Russian Internet users aged 14-55 among all Russian-language resources.
A new service has emerged since January 23, 2009, which allows you to clear the page of uninvited guests by removing them from the list of views. You can now also close the page from everyone but your friends.
After the introduction of paid registration in 2008, the popularity of the site fell sharply and users began to go to the main competitor VKontakte. On August 31, Odnoklassniki canceled user registration fees, and became free again. The Odnoklassniki social network has more than 45 million registered users. According to TNS Web Index, 56% of the audience are users aged 25-44. The share of managers and specialists is 19% and 28%, respectively.
In early April, 2010 beta testing games appeared on the site, the developers were i-Jet.
On December 24, 2010 users of the Odnoklassniki social network got the opportunity to test the beta version of the video chat.
Service blocking in Ukraine.
In May 2017, Ukrainian President Petro Poroshenko signed a decree to impose a ban on Mail.ru and its widely-used social networks including VKontakte and Odnoklassniki as part of its continued sanctions on Russia for its annexation of Crimea and involvement in the War in Donbass. The move was widely criticised as censorship, and Reporters Without Borders condemned the ban, calling it a "disproportionate measure that seriously undermines the Ukrainian people’s right to information and freedom of expression." Respondents in an online poll on the UNIAN site declared that 66% were “categorically against” the ban of Russian sites and another 11% said it would be easier to “ban the whole internet, like in North Korea”. 
According to the Internet Association of Ukraine the share of Ukrainian Internet users who visit Odnoklassniki daily had fallen from 35% to 10% from September 2016 to September 2019.
Paid registration and services.
From October 2008 to September 2010, only a limited functionality account could be registered for free. In this version it is impossible to post, upload and rate photos, leave comments in forums and visit other users' pages. In order to use these features, a paid short message had to be sent. In addition, the site provides a number of paid services: deleting ratings and good ratings of their photos, disabling the message that the user is online, providing a wide range of smiles.
Currently, it is free to delete ratings of your photos as well as guests from your watch list.
On August 31, 2010, social network management canceled paid registration. The official reason was "developing new effective ways to combat spammers".
In February 2016, the social network, together with its partner bank VTB 24, introduced the ability to make money transfers between users of the network. Transfers are made between MasterCard, Maestro, Visa payment cards issued by Russian banks and linked to user profiles.
Technology.
The server that hosts odnoklassniki.ru is located in Moscow, Russia on the Golden Telecom network. The programming language used on the site is Java and the main language used for the site's textual content is Russian. The site uses the Apache Tomcat web server.