If you're completely obsessed with checking your Facebook updates every few minutes, then I've got something for you. Facebook quietly launched a new official desktop application called, "Desktop Notifications" which notifies you anytime an update occurs to your profile. Although in its very early stages and only available for Mac users, the application is functioning as it should on my machine and is pretty neat.
Unlike Tweetdeck a third party desktop application which has the same capabilities but runs on Adobe Air, this is native in itself (doesn't need anything else to get running). During install, Facebook asks the user to sign on with its very own, Facebook Connect.
Once the user is all set up, the application loads up and lives up on Apple's top menu bar. From here, the user can click the official Facebook icon and check what sort of updates are happening on their profile.
Unfortunately, and probably since the app is in such early stages, when you click on those updates, you'll be taken to your default browser to whatever that notification is.
A couple pretty neat features are what the app allows a Facebook user to do all from their desktop. The first being updating their status. Either by key command, or clicking the drop down menu and 'Update Status', a neat little box pops up where you can update from your desktop and it automatically appears on your Facebook page without you ever having to go there.
And when it appears on Facebook, it says the update came from the "Desktop Notfications" application.
Another key feature to the application is the little pop-up notifications that appear either with a 'Growl' sound effect, which can be turned off if desired so. Basically anytime somebody posts on your wall or you receive an message, popups let you know whats going on. They are very subtle and don't seem to affect whatever your working on at the moment.