Would you like to be able to click an icon on your desktop or start menu and go right to your favorite web application like twitter, gmail, facebook, etc? If so, you might want to check out PRISM.
Prism is an application that lets users split web applications out of their browser and run them directly on their desktop. Prism opens up your applications (such as Facebook) without all of the regular browser menus, so in this case, only Facebook will run in the browser.
It is developed by the Mozilla folks (they bring you the Firefox browser) so it is a name you can trust.
Here's a screenshot of my Twitter page running in a Prism application. This is running in a "Firefox like" window, but it does not have all of the other baggage of a browser. No more opening bookmarks, tabs, extra browser windows to get to my Twitter page.
Prism apps run more stable and are less prone to bugs and browser crashes. If Firefox crashes, your Prism apps are not affected.
Learn more about Prism at prism.mozilla.com