Earlier this year Valve decided to stop returning items to victims of scams, meaning that people who got duped out of their precious gear were on their own. To lower a chance of this happening Valve are now implementing a "trade hold" into Steam which will delay any trade for three days if the user isn't protected by Steam's mobile authenticator.

This should give anyone whose items have been traded without their knowledge enough time to stop the trade and get the items back. Also, if a trade that is being held gets cancelled a trading cooldown will stop any future trade attempts from happening.

While the trade hold option is a way to prevent item theft and scams, it is also a good incentive for more people to use Valve's Steam Guard Mobile Authenticator, as anyone using it can trade normally.