VK is an all-purpose tool for finding friends, considered a Russian version of Facebook.
http://vk.com/
JavaScript Libraries and Functions · Social SDK
Get access to data on 783,168 websites that are VK Customers. We know of 304,252 live websites using VK and an additional 478,916 sites that used VK historically and 34,292 websites in the United States.
Get a list of 783,168 websites using VK which includes location information, hosting data, contact details, 304,252 currently live websites and an additional 71,195 domains that redirect to sites in this list. 478,916 sites that used this technology previously and 34,292 websites in the United States currently using VK.