I think you meant by the links in peoples' signatures? It's hard to prevent that, Mace did allow people to advertise in signatures as long as they don't make topics or posts about it.
Leaving threads have been going on for a long time, people do tend to try to grab attention. But again, Mace said he's going to make a thread for the public, so they can post if they are going to leave for a break or forever.
I am guessing we just need to be patient.