In the last year, I've convinced 5 or 6 people to start using RSS in general and Google Reader specifically. Without a doubt, one of the first questions they ask after understanding the technology is, "OK, what feeds should I read now." I think what happens is people recognize what they'll be able to do with RSS (follow their favorite websites) and they want to do more of it.

Google makes it easy to share specific items from your feeds with your friends, going so far as to give you a personalized page with your shared items on it (careful, you might just start a blog by accident). However, there's currently no way to share which feeds you're subscribed to making it hard to truly evangelize this product. Get on that Google.