AddThis
629,840 websites

AddThis is free to use

http://www.addthis.com

AddThis, the new brand name for Clearspring Technologies, is the leader in socially connecting publishers, services and advertisers to audiences on the open web. Reaching more than 1.3 billion unique users monthly, AddThis’ social tools and...

VS

Twitter Button
837,185 websites

Twitter Button is free to use

https://about.twitter.com/resources/buttons#tweet

The Tweet Button is a small widget which allows visitors to share content and connect on Twitter.

Market Share by Top Websites

1 Twitter Button is leading in Top 10K Sites and The Entire Web.

2 AddThis is leading in Top 100K Sites and Top 1M Sites.

Websites Categories

1 Twitter Button has better usage coverage in more websites categories. Including Arts & Entertainment, Computers Electronics & Technology, Food & Drink, Science & Education and 18 other categories.

2 AddThis is leading in Law & Government and Heavy Industry & Engineering.

Geography

1 AddThis is leading in most countries, including United States, United Kingdom, Italy, Canada and 122 other countries.

2 Twitter Button is leading in Japan, France, Czech Republic, Mexico and 32 other countries.