Per Google:
"+1 is as simple on the rest of the web as it is on Google search. With a single click you can recommend that raincoat, news article or favorite sci-fi movie to friends, contacts and the rest of the world. The next time your connections search, they could see your +1's directly in their search results, helping them find your recommendations when they're most useful."
If you want to use +1, simply click a +1 button when you first come across one and anything you +1 from that day forward will appear in a +1 tab that lives inside your Google profile. As Google specifies, "While your +1's are public, the +1's tab on your Google profile is viewable only to you unless you specify otherwise." You can delete +1's, too.
Source: techland.time.com