This +1 button is a Google tool to let your friends know about web pages you have found interesting and want to share with them. The +1 button is shorthand for "This is pretty cool!" or "You should check this out."
The +1 buttons can help your friends, contacts, and others on the web quickly see the same interesting and fun web pages you found. The only requirements are to be signed into your Google Account and click the +1 button on the web pages that you want to share with your friends and contacts.
This is yet another way on the Internet to connect with people all over the world. (Ain't it great! Give it a try!)