The Microsoft-made app requires .NET 3.5, and will install it for you automatically if you don't already have it. When it first runs it will ask for your Facebook login, as well as permission to publish posts without prompting you, and also to allow the program to access your News Feed and Wall.
Fishbowl displays a left-side list of feeds that matches what you'll see on Facebook's page, starting with the News Feed. But it tends to display feeds differently than how they'd look in your browser. For instance, it enlarges and slightly tilts your friends' profile pictures, which makes them stand out more.
The app also differs in the way it handles your Facebook friends. You can choose from a low, medium or high "Interest Level" for your friends, and then allow you to view them them based on your assigned interest. Other features allow for a mini-mode, a small display with just the latest update, and a row of friends' pictures that link to their profiles.
If you're a Facebook fanatic you might like Fishbowl's different layout, but the app doesn't offer any must-haves. If you do try it, keep in mind that Microsoft bills it as an experimental program and doesn't offer any support. Also, you can still visit your account in a browser as per usual after trying Fishbowl.