Yes, the only requirement to join is that you will have somethingto do with OFMM. It's not Facebook.
What is there to do? There is lots to do there:
You used to have to sign up
here to join as a pilot, but I'm not sure of that any more.
Signup is different for OFMM lite, go
here.
You can sign up for development in the thread linked to in my signature.
You can also chat or send updates on the #OFMM IRC channel.
All the OFMM lite G1 missions are taken, but don't be worried if you want to pilot. There is a good chance of an OFMM lite G2 happening, and let's not forget the actual OFMM!
So, thanks for your interest!
And now, finally, there is a place to put this poster!