Good question! I touched on revenue/privacy on this blog drop: glue.im/glue/glue-a-social-net...
Also, we run our own server hardware and I've been building our own infrastructure for over a year now to run Glue (and other apps) cost-efficient.
Thanks. Very clear and easy to understand. I also learned a couple other useful things. I'm a fan, just need to figure out the social parts better (as the user base grows!)