If you granted access to some of your data in Google (analytics, calendar, contacts, etc.) to some external application (like Xobni for example); you may want -at some point- to revoke them as you no longer use that application.
To do that click on the gear icon and select “Account settings” go to your account settings once you’re logged into Google:
then click on “Authorizing application & sites” link:
In the following page click “Revoke Access” to any application you no longer use. That ensures that none will be able to see your private data with that particular application.