3) Ping.fm What It Does: Lets you post updates from Facebook to tons of other social sites, including MySpace, Tumblr, Twitter, Hi5, and even LiveJournal.
Why You Need It: Logging into one site is enough of a pain. If you're updating your Facebook status, you might as well cross-post to a few other sites as well, to make sure you reach your friends who remain Facebookless. There's also posting by email, over AIM or GTalk, or through mobile apps.
File Sharing4) Drop.io Feed ConnectWhat It Does: Lets you share files directly through your Facebook feed, by updating the feed whenever you upload something to a Drop.io "drop" that's connected to Facebook.
Why You Need It: File sharing on Facebook has always been a hassle, and Drop.io seems to have the best solution going right now. The "feed connect" idea was developed spefically for the latest iteration of the Twitter design, and works with it where some apps work against it. Drop.io made a name for itself by building an easy drop-to-upload interface, and it's a natural fit for Facebook.
5) DivshareWhat It Does: Adds file sharing either directly to a friend, through your profile, or in your stream.
Why You Need It: Divshare can't touch Drop.io connect in terms of sharing in the stream, but if you want to zap a file to another Facebook user, or just keep it on your profile, Divshare is the app for you. It has the added bonus of having been around for a while, so there's a good chance some of your friends are already using it.
Games6) ScrabbleWhat It Does: Lets you play Scrabble with your Facebook friends, and also has a matching iPhone app so you can play on the go
Why You Need It: After Scrabulous, the popular unofficial version of Facebook Scrabble, got shut down, it was replaced with this licensed version. Although it can be glitchy and unreliable at times, Scrabble is still the best game on Facebook.
Music7) Last.fm Music and 8) What I'm Listening To
What They Do: Last.fm music lets you share playlists with your friends on Facebook via the popular Last.fm social music site, and What I'm Listening To shows your recently-played tracks on Last.fm.
Why You Need It: Because everyone knows that the way to impress people on Facebook is by declaring your awesome musical taste. It's one thing to carefully pick the bands you list in the favorite music section of your profile, but you can walk the walk instead of just talking the talk if you show people what you're listening to on Last.fm. Last.fm Music also compares musical compatibility with your friends, just for fun.
9) PandoraWhat It Does: Links your Facebook account with your Pandora account, so it can display your favorite artists and songs, and your recent stations.
Why You Need It: Maybe you don't use Last.fm, but Pandora is your music discovery engine of choice. In that case, this app makes an attractive addition to your profile. It shows 4 recent stations, 3 favorite artists, and some of your bookmarked tracks from Pandora. Friends can open your Pandora stations with one click, too.
Other10) Appear OfflineWhat It Does: Allows you to see who's signed on to Facebook Chat without having Facebook chat activated. You can poke and send Facebook messages to your online contacts from the Appear Offline page.
Why You Need It: Because sometimes Facebook chat is a nuisance, and you just want to turn it off. This way, you can turn it off without losing the ability to see which of your friends are online.