Google's new +1 button is undoubtedly becoming familiar. It shows up next to search results, next to adds, and next to posts and comments in their new social network Google+. It means simply that you approve, like or recommend the site, article, post or comment in question. Google has a description of the +1 button on the web.
It is important to note that if you +1 a site or article on the web (but not for posts and comments in Google+), it may show on your profile. There is a tab devoted to +1's. You have control over whether this tab shows on your profile. Edit your Google profile, go to the +1 tab, and uncheck "Show this tab on your profile" if you want a little more privacy.
The real reason for this post however is that there are a few helpful extensions for +1. Not every news site or blog has the +1 button yet. The Plus One extension for Chrome gives you a +1 button for any website you visit. For those still actively using Facebook, the +OneFB extension for Chrome gives +1 buttons on Facebook. If someone shares a link on Facebook, you can Like it and +1 it. Finally, the 1-Up for Google+ extension for Chrome turns the +1 button on Google+ into a Mario Brothers style 1-up mushroom.