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

Zendesk
764,132 websites

Zendesk offers both free and paid options

http://zendesk.com/

Zendesk provides an integrated on-demand helpdesk - customer support portal solution based on the latest Web 2.0 technologies and design philosophies. The product has an elegant, minimalist design implemented in Ruby on Rails and provide...

Market Share by Top Websites

1 Zendesk is leading in Top 10K Sites, Top 100K Sites and The Entire Web.

2 AddThis is leading in Top 1M Sites.

Websites Categories

1 Zendesk has better usage coverage in more websites categories. Including Arts & Entertainment, Games, Adult, Lifestyle and 10 other categories.

2 AddThis is leading in Science & Education, Health, Law & Government, Sports and 6 other categories.

Geography

1 AddThis is leading in most countries, including France, Italy, Brazil, India and 129 other countries.

2 Zendesk is leading in United States, United Kingdom, Canada, Japan and 28 other countries.