Your posts will increase your star rank.
20000 to get to 5 full stars though. No spamming and posting on pointless game thopics though, they will probably only get deleted anyways.
Back on topic-
I just got Crackdown today...playing it right now actually. And it has the beta download option although it says to come back at a later time.
* Updated game trainers and cheats daily
* Get notified when new cheats are added
* Request which games get new trainers
* Priority support with any problem