I'm certain the OP of the threads you shared broke a forum rule and judging by the post from Theymos I quoted below(the rule is from "invites & accounts" sub board). so he would either get banned or get his posts deleted if you reported it to the mods.
You are only allowed to sell accounts/invites that you legally obtained yourself or through legitimate trades. If you did anything illegal in order to obtain an item, then you can't trade it on bitcointalk.org. Anyone found breaking this rule will be banned.