On the social point... I like foursquare type check-in apps because they work to segregate check-in activity for people who're interested in it. I don't post "I

On the social point... I like foursquare type check-in apps because they work to segregate check-in activity for people who're interested in it. I don't post "I'm at Restaurant X!" on facebook/twitter, because I'd feel like I was spamming people... but if I check in there on foursquare, I know that the people who see that are other people who've decided they want to use foursquare. It's still a social sharing activity, but it's done with a carefully selected subgroup.