Having had enough with the impulse chat overlay, I created a STEAM group for Demigod. If enough people use the overlay, it might help people get games set up. This might totally flop, or it might work well. It's just an experiment.
Here's the link:
Join it, and let's see what we can get going. You can add DG as a non-STEAM game, and you'll be able to see messages sent to you. Shift+Tab doesn't work with the overlay, so you'll have to alt+Tab to reply to messages.