GameFly's digital PC client has left beta and officially launched, offering access to more than 1,500 PC and Mac games. If you happen to be a paying subscriber, you'll be able to take part in Unlimited PC Play which includes "hundreds" of PC titles playable for free.
Another digital distribution platform might not seem like something we desperately need more of right now, but the aforementioned benefit could work out well for GameFly members, if nothing else; it'll mostly depend on what games actually end up being featured. Additionally, the company is offering BioShock for free right now if you download the client. That's certainly one way to get more installations.