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Why would anyone trust you with their money?
I suggest having a x/y multisig wallet and get few users from the forum on board with you. So to release a tx you will need more than one signature and the risk is less for the buyers and sellers.
A 2-of-3 multisig escrow address with a hypothetical malicious escrow agent could conspire with one of the parties of the transaction to steal the coin in the escrow address.
I am not saying the OP is acting maliciously, however, based on his current reputation, it would be difficult for an experienced forum member to use the OP as an escrow agent.