GR definitely seems more social than LibraryThing. I partially imported my library from LT, it choked over the manga and Japanese books and fucked with my tags and just ended up all sorts of messy and blah so I haven't really touched it since then, however, I get a pretty steady stream of notifications of people liking my reviews and such, so there seems to be more interaction than on LT. At some point I'd like to clean it up and start using it more, but it just feels like such a hassle. I wish I had heard of it first rather than LT...