+1

The +1 button and search results
How does +1 affect search results? Does +1 affect my site’s performance in search? How will the +1 button affect my traffic? Will +1’s from my site show up in search results? How does the +1 button affect my ads?
Who sees +1?
Who can see the +1 button in Google Search? Who can see annotations from +1 buttons? Will users on mobile browsers see the +1 button? Are +1's public?
Adding the +1 button to a site
How do I add the +1 button to my site? Where should I put the +1 button on my pages? Can I place multiple buttons on a single page that all +1 different URLs? What languages is the +1 button available in? How often will Google crawl my +1'd pages? How does +1 work with Buzz? Do we still need the Google Buzz button? Some of my users get a security warning when they view pages with the +1 button. How do I get rid of this?
Configuring the +1 button
What button sizes are available? What does the "Language" drop-down control?