Yeah! It's been interesting figuring that part out. An unexpected issue I ran into with my weekly raffle prizes to tippers was that I had no way of contacting only app users to let them know they won an art request. I could leave a message on their wall after trying to find their wall on the site, however they aren't notified on the app if a message is left on their wall, so a lot of raffles went unclaimed.
This month, with that issue in mind, I made the tipper reward more open where they could comment on an episode, tweet at me, or message me to claim a avatar image.
I'll be glad to get some helpful tools for this process.