The page embeds the Twitter platform in one method or another.
http://twitter.com/about/resources
JavaScript Libraries and Functions
Get access to data on 9,414,761 websites that are Twitter Platform Customers. We know of 2,434,476 live websites using Twitter Platform and an additional 6,980,285 sites that used Twitter Platform historically and 1,287,336 websites in the United States.
Get a list of 9,414,761 websites using Twitter Platform which includes location information, hosting data, contact details, 2,434,476 currently live websites and an additional 2,539,296 domains that redirect to sites in this list. 6,980,285 sites that used this technology previously and 1,287,336 websites in the United States currently using Twitter Platform.