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 886,615 websites that are VK Customers. We know of 277,382 live websites using VK and an additional 609,233 sites that used VK historically and 29,533 websites in the United States.
Get a list of 886,615 websites using VK which includes location information, hosting data, contact details, 277,382 currently live websites and an additional 79,712 domains that redirect to sites in this list. 609,233 sites that used this technology previously and 29,533 websites in the United States currently using VK.