Just over a month ago Valve had to step in to help users who were becoming the victim of trades gone wrong when dodgy payments used to buy a game sometimes left one side of the trade with nothing after the game was revoked by Steam. Now they're stepping in again to tackle another trade related issue, this time to do with malware clearing out accounts.
A new Captcha system is being put into place for all trade offers that go through Steam now, in an attempt to stop malicious programs that are designed to access users' accounts and make trades on their behalf, thereby clearing out the account in question.
"We’re updating trading to include a captcha as part of confirmation process.” said Valve in an announcement about the change. “This is to prevent malware on users’ machines making trades on their behalf. We know it’s a bit of a hassle, and we don’t like making trading harder for users, but we do expect it to significantly help customers who are tricked into downloading and running malware from losing their items."
It's a nice step towards a more secure process, but unfortunately it seems its implementation has reset the trade system - cancelling all current and pending trade offers which has angered some users. Valve is looking for input on the system over on the Steam forums though so feel free to hop over there to have your say.