OK (Odnoklassniki) is the largest European online social networking service, based in Russia.
It is available in several languages, and is especially popular among Russian-speaking users.
OK allows users to message each other publicly or privately, to create groups, public pages and events, share and tag images, audio and video, and to play browser-based games.
Advertising Odnoklassniki is one of the best solutions to extend the reach of your customers.