I frequently append site:reddit.com to searches for a niche search term these days. I think a lot of people who would have blogged or commented on blogs are posting there instead.
I wonder if they'll do a walled garden after their IPO. I've always found the site pretty useless, outside the 'old.reddit.com' version. On the bright side, maybe this will open up space for one of the federated clones to grow.