The odds are pretty good that the post you saw were for sites that promote piracy and such. As a result, they'd have been automatically edited/deleted by a moderator cause piracy is not accepted at this forum.
The safest thing to do, as a new jailbreaker, is to use Cydia. Its owner, saurik, hosts it and other repositories feed into it. The official, sanctioned sites that saurik has auto-load on your iPad are ones that don't promote piracy. In essence, if it's a legal tweak, Cydia will have it.
Yes, there are other sites, but since it's such a hassle to find repos that carry legal stuff, I find it easier to stick with Cydia.
Marilyn