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 826,222 websites that are VK Customers. We know of 266,280 live websites using VK and an additional 559,942 sites that used VK historically and 29,890 websites in the United States.
Get a list of 826,222 websites using VK which includes location information, hosting data, contact details, 266,280 currently live websites and an additional 89,246 domains that redirect to sites in this list. 559,942 sites that used this technology previously and 29,890 websites in the United States currently using VK.