This is the reason why some of the groups have been deleted:
http://www.edge102.com/contests/in_the_facebook.cfm
Basically what they say in the video is don't spam people with invites to join the group. People have probably been getting annoyed at the amount of invites they received (Karthik said he got around 30), and Facebook decided to delete the groups that were spamming. I think it would be a good idea to try and send invites only to people that you think will actually join (people that have experience with FISRT?!).
The group is still around and is actually pretty high in the standings. It wouldn't be fun if it got deleted now.