I think its tough to run a social network today and not be tempted to milk your users for everything a la facebook. Reddit does a reasonable job imo (and is being rewarded with good communities building there) though you can see the app is a bit of a grab in that direction (otherwise theyd just make the mobile web experience better). Hopefully their trajectory will stay positive though as always people will move on if bad decisions are made (a la slashdot, kuro5hin, digg, etc)