The Reddit voting widget.
http://reddit.com/buttons
Widgets · Social Sharing
Get access to data on 1,307,873 websites that are Reddit Customers. We know of 211,317 live websites using Reddit and an additional 1,096,556 sites that used Reddit historically and 138,309 websites in the United States.
Get a list of 1,307,873 websites using Reddit which includes location information, hosting data, contact details, 346,693 currently live websites which includes 135,376 domains that redirect to sites in the list. 1,096,556 sites that used this technology previously and 138,309 websites in the United States currently using Reddit.