To all the leeches in this thread: I suspect that anyone you know with a large number of games is instantly going to get bombarded with sharing requests, and it's going to make them resent those people and also feel like they're only being talked to because they have cool toys. Unless you want to alienate people, don't ask them to share their library with you.
Yeah, and even if you do get on their list you're potentially splitting it with 10 other people.
I feel like it gets better the fewer people in a sharing ring there are. And on that note, this will be great for me and my brother since we have somewhat different tastes and aren't always playing PC so sharing conflicts won't be that big a deal.