hehe very nice on the free stuff.
in regards to this site however.
I have been using it and their affiliates under the same network run by same people for quite a while, and don't recieve much junk mail at all.

you don't give your credit card to them, only to the people who you sign up with.
and people you're giving it to are reputable (AOL, eBay, etc.).

so yeah it is legit, but like you said, there is a nasty catch, it's really annoying/hard to get other people to sign up under you.