I'm on a Mac, too. ~/Documents/Steam Content/ is where Steam dumps all its content on a Mac. The "Properties" option is in the context menu when you right-click

I'm on a Mac, too. ~/Documents/Steam Content/ is where Steam dumps all its content on a Mac. The "Properties" option is in the context menu when you right-click on Portal in your games list in the Steam client, and that brings up another Steam box that lets you verify the local game cache. I wasn't referring to the Windows Explorer "Properties" option (which I think you thought I was referring to).