There needs to be separate restrictions on the Marketplace (especially Goods, Currency Exchange, and Lending sub-sections). Seems like every godamn newbie heads straight for one or more of those sections as soon as getting out of the sandbox.
And notice those that do get hammered for it. Might be a harsh "self regulation" but the trolls are waiting for the newbies in lending and other places - that's why doing homework helps.
Some of them are a little overzealous, but yes self regulation works pretty well there for the most part.