Facebook introduced new guidelines this month for "contests" and "sweepstakes" that are worth a read if you're planning on creating or using a Facebook Page promotional purposes.
In brief, Facebook is clamping down on the use of Facebook's existing features i.e. becoming a fan of a page, uploading a photo, writing a wall post, etc. as mechanisms for entering contests. If you are running a contest with a prize then it must be run as a third-party application on a tab on your page. Most importantly, Facebook must approve it with at least seven days advance notice.
So, no more using your Facebook presence for something spontaneous to engage the brand community you've built on Facebook for your brand or organization. Our client, Motorola Canada, routinely gives away concert tickets to its Facebook community by entering a contest on a tab, but that tab isn't an application and it isn't approved by Facebook in advance. It would seem that's outside of what's acceptible under the new guidelines. (Edit: because you have to be a Fan of the page to enter.)
Bottom line: It's going to cost more and you're going to need more lead time to create promotional programs on Facebook. That may leave small charities and small businesses that have built up a loyal Facebook community looking for a new place to run contests and sweepstakes.
I understand Facebook's position. They want to maintain control over their platform and ensure that their members are treated fairly and with respect. But, if you want to do something fun on the spur of the moment, you're left with telling your "fans" to head over to Twitter.
Some other takes on the news guideilines: