Prior to about two weeks ago I was a reluctant and infrequent Facebooker. Even when all my friends migrated over from Friendster(!) and MySpace I still really only logged on to accept friend requests (I'm kind of a big deal.)
That was until I installed the Scrabulous application at the behest of my friend Anthony who promised it would "change my life". Oh. My. God. In about 24 hours I went from a once a week Facebooker to logging in 3 - 5 times a day (because in a genius move Scrabulous doesn't ping you when it's your play - causing you to casually stalk your own games.)
Now, in my memory I was a decent Srabble player, but I quickly found myself getting annihilated by people who call themselves my friends, but are in fact undercover Scrabulous Grand Masters. While I'm looking for an opening to lay down long words like CRUCIBLE (which gets you like 7 points it turns out), they are going all ninja on me with high value plays like ZIEN (a protien of the prolamin group) and QUIRE (a quantity of paper) and OVA (that would be the plural of ovum...something to do with mature eggs that none of us want to know about.) I'm gradually improving - which of course requires more hours of actual game play.
With 500,000+ daily users, over 2 million applications installed and nearly 4,000 fans, Scrabulous stands out in the field of totally ridiculous and superfluous Facebook apps. The reason it works is that first and foremost it's a utility. People like it because it actually DOES something for them. Corporate America could take a page out of Scrabulous' book - skip the silly branded games and lame gifts and design apps and widgets that provide value, lead to engagement and facilitate community.