The other day I noticed a new change in the Facebook API: Absolute URLs to sites outside of Facebook are no longer supported in the fb:action FBML tag.
I guess the idea is to keep people inside Facebook. I wouldn’t be surprised if the same restriction were applied to all absolute links within the canvas page and profile boxes (can you say good bye 3rd party ads!). That would make a lot of sense since right now, application developers that choose to use third party advertising networks (Google, Cubics, SocialMedia, i.e.) don’t have to share any of their revenue with Facebook but instead get paid to send traffic out of Facebook! I cannot image this will go unchecked for too long.
A handful of popular Facebook applications from companies like RockYou and Slide, as well as social media ad networks (Buddy Media) command a sizeable amount of traffic on Facebook and probably comparable ad revenue streams. My guess is that Facebook will soon add social ad support directly into the Facebook API and become the de facto ad network for all Facebook apps, forcing developers to share the spoil!
In the mean time, if you plan on using the fb:action tab in your menus you should either
- point it to an internal Facebook Fan Page or
- create a redirect Facebook application page in PHP that uses the Meta refresh to do the trick!