As Google puts it, “The +1 button is shorthand for ‘this is pretty cool’ or ‘you should check this out.'”
You can see +1’s from friends, contacts or anybody, and you have the option to keep your own +1’s public or private.
Before you can use the feature, however; you have to be logged in to your Google account and have a Google profile.
The feature isn’t live yet, but users can activate it if they want to try it. The +1 button will also begin appearing on websites across the Internet.
Google has more details on the feature at its official blog.