How the +1 button respects your privacy
Does Google track my visits to pages with the +1 button even when I don’t +1 something?
The +1 button isn’t used to track your visits across the web. Google doesn’t keep a persistent record of your browsing history as part of the process of showing you a +1 button or otherwise use the fact that you personally have visited a page with the +1 button.
Google may keep some information about your visit, usually for about two weeks, to maintain and debug its systems. This information isn’t organized by individual profiles, usernames, or URLs.
Why does Google need this information?
When you do a Google search or visit a page with a +1 button, we send different pieces of your request to separate servers -- which helps the +1 button load quickly. To ensure those servers are processing your request correctly, and in the rare cases where we need to debug our systems, this information helps us find the source of the problem between servers and fix it.
How long do you keep this information?
Usually less than two weeks.
Do website publishers or advertisers see this information?
No, this information is used to maintain and debug internal systems. Learn more about the +1 button on non-Google sites.
What data is sent to Google when you click +1?
In order to store your +1 and make it visible to the public, Google receives information about your Google profile, the URL you +1, your IP address, and other browser-related information. If you undo your +1, this information will be deleted. You can see all your +1’s in the +1’s tab of your profile.