In light of the individual who just had his account hacked and 500k worth of bitcoins stollen... I thought of an idea.
We know the wallet address that recieved the funds... Since we know the wallet address, couldn't we track the transactions this guy makes and note them somewhere? It's very likely that eventually, the individual exposes his identity by ordering something. It would be possible to track the exchanges made to and from the address that recieved the stolen funds.
Perhaps there should be a database that tracks addresses known to be involved with theft such that merchants would have the option to check addresses and help catch the criminals. Although, it would have to be designed so that it could not be abused such that the likelihood of it being used to harm someone innocent is minimalized.
Just an idea.