Account Manager for Firefox
Account Manager is an experimental Firefox extension that lets you login and logout of web sites by clicking the Account Manager button to ‘Connect’ and ‘Disconnect’ from your online account. It makes the whole damn process of getting in-and-out of web sites easy. The project went public a month ago but then testing wasn’t possible . Now you can try it on web services like Facebook, Google, Mozilla Add-ons, Yahoo and a few others, provided Firefox is enabled to store your passwords. Account Manager for Firefox is not customizable — for now.
Mozilla intends to eventually integrate Account Manager into Firefox as an in-built feature, now you can have it as a free to download Firefox add-on.