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 9,730,952 websites that are Twitter Platform Customers. We know of 2,229,001 live websites using Twitter Platform and an additional 7,501,951 sites that used Twitter Platform historically and 1,242,127 websites in the United States.
Get a list of 9,730,952 websites using Twitter Platform which includes location information, hosting data, contact details, 2,229,001 currently live websites and an additional 1,529,563 domains that redirect to sites in this list. 7,501,951 sites that used this technology previously and 1,242,127 websites in the United States currently using Twitter Platform.