push notifications to users that opt-in, so they can join in

[brimonk]

It might be exhausing to know, but I would like the ability to get a push notification of some kind (email, mobile notification, w/e) that a new public game has started, so I can join in.

I like to think this would allow for spontaneous games with LOTS of people, without any player advertisement, but it could just be really annoying.