Hubki's collaborative feel (and that beautiful picture of the Croatian coast) is what got me on this train of thought. For the first time in a long time, I'm cautiously optimistic about participating in an online community. From what I've seen, the peeps participating are wicked smart and mostly respectful. It would be awesome to have that community in real life--to just take over an entire block in some out-of-the-way coastal town with a great library and fast internet. A man can dream...
I love the collaborative feel on this site as well. Unlike Reddit, which is designed as a bunch of mini-feifdoms in which one can isolate themselves, the Hubski design is better at getting people with various interests to talk to each other. Everything is on a single global feed, users can pick out parts of the feed they find interesting by following people, domains and topics, and content propagates through sharing rather than a battle for up votes.