I love the recent Y! acquisition, mybloglog. Its like a myspace with bells on. Ive encountered some really nice and interesting people too. In case you haven’t seen or used it before its a social media platform. You can join communities, add contacts, upload photos and if you install a piece of code you can get stats and display photos of visitors from their network on your site as they arrive.
On the user front I think its kinda cool. IMO I think It adds an extra dimension to ones website by way of showing an extra human dimension. You can see the latest faces of people who have visited and if you so feel inclined, go and check them out to see what they are all about; at least thats what Ive found myself doing!
Their stats page is cool too. Gives you a non fussy overview of where your readers came from, what they viewed and what they clicked. It even tells you what ads they clicked on too.