The Share with Facebook Accelerator allows you to share any text, link, or page with your Facebook friends with a single click. You can use this accelerator by selecting either some text or a link, or by right-clicking on any part of the page.
Install here: http://www.ieaddons.com/en/details/204/Share_on_Facebook/
The technical beauty of this add-on is that it is extremely simple. In fact, it is contained in a single XML file, which is based on the OpenServiceDescription specification.
The Facebook Web Slice allows you to stay up to date with what’s happening in your Facebook network. Regardless what website you are on, you can click at any time on the web slice title and display the recent messages from your friends on your board.
Install here: http://www.ieaddons.com/en/details/social/Facebook_Web_Slice/
The Web Slice uses the Facebook Connect APIs to connect to your account and it shows a notification when new content is available. Special thanks go to the MVP Konstantinos Pantos for his contribution to the community.
Do you need to search for someone on Facebook? You can start right away from the browser search box!
Install here: http://www.ieaddons.com/en/details/searchhelpers/Facebook/
Again, this extension is built on top of an XML file which describes the end-point for the search provider.
The Facebook Toolbar lets you to share with your friends while browsing anywhere on the web - get notified, share content, upload photos, and update your status no matter where you are!
Install here: http://www.facebook.com/toolbar#!/toolbar?v=app_4949752878
The source code of this toolbar is available on github.