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 4,771,751 websites that are Twitter Tweet Button Customers. We know of 1,129,271 live websites using Twitter Tweet Button and an additional 3,642,480 sites that used Twitter Tweet Button historically and 574,907 websites in the United States.
Get a list of 4,771,751 websites using Twitter Tweet Button which includes location information, hosting data, contact details, 1,129,271 currently live websites and an additional 833,917 domains that redirect to sites in this list. 3,642,480 sites that used this technology previously and 574,907 websites in the United States currently using Twitter Tweet Button.