It's not good to post your Steam ID as your account might get banned by Steam if someone reports you.
Yeah this is true. Try not to show anything that can be shown to be your account. If they find out you sold it, its possible that they could ban your account perm. Also, I do suggest that if you do sell it, use Crackedlogic as a escrow. I've have dealt with him before and deem him trustworthy. But its your decision. GL on selling your games.