Official Tweet Button for sharing articles on websites and counting how many times a URL has been shared.
https://twitter.com/about/resources/buttons#tweet
Widgets
Get access to data on 4,694,594 websites that are Twitter Tweet Button Customers. We know of 1,443,225 live websites using Twitter Tweet Button and an additional 3,251,369 sites that used Twitter Tweet Button historically and 719,846 websites in the United States.
Get a list of 4,694,594 websites using Twitter Tweet Button which includes location information, hosting data, contact details, 1,443,225 currently live websites and an additional 1,260,980 domains that redirect to sites in this list. 3,251,369 sites that used this technology previously and 719,846 websites in the United States currently using Twitter Tweet Button.