Google +1 Button
597,414 websites

Google +1 Button is free to use

https://developers.google.com/+/web/+1button/

Let visitors recommend your content on Google Search and share it on Google+.

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Pinterest
292,411 websites

Pinterest is free to use

http://pinterest.com/

Pinterest is a social networking site with a visually-pleasing virtual pinboard interface. Users collect photos and link to products they love, creating their own pinboards and following the pinboards of other people whom they find interest...

Market Share by Top Websites

1 Google +1 Button is leading in Top 10K Sites, Top 100K Sites, Top 1M Sites and The Entire Web.

2 In terms of market share, Pinterest is clearly lagging behind, losing to Google +1 Button in all segments.

Websites Categories

1 Google +1 Button has better usage coverage in more websites categories. Including Computers Electronics & Technology, Arts & Entertainment, Science & Education, Travel & Tourism and 16 other categories.

2 Pinterest is leading in Food & Drink, Lifestyle, Home & Garden and Hobbies & Leisure.

Geography

1 Google +1 Button is leading in most countries, including Japan, France, Italy, Russia and 153 other countries.

2 Pinterest is leading in United States, Argentina, New Zealand, French Polynesia and 4 other countries.