Imzy is a social media platform created by some Reddit alumni who seem, quite reasonably, to hate Reddit culture and to be interested in running a site that prevents and discourages some of those specific excesses. Design-wise, it owes as much to Tumblr and LiveJournal as to Reddit, I’d say. Activity is nearly 100% community-based and you have a dash, basically, that aggregates posts from communities you follow. The format is discussion-oriented, with threaded comments. My “blog” is actually a one-man community; you can set up a blog so that other people can post to it, like a Facebook wall.
Tumblr’s future is uncertain, and it’s always been an absolutely god-awful platform in many respects (especially for discussion), so people are looking for alternatives; Imzy’s currently getting a pretty substantial fandom push. This is mostly centralized around the fail_fandom_anon community there, but communities for specific fandoms and fandom activities (writing, vidding, etc) are springing up rapidly. I have some misgivings about it, but it’s not even feature-complete yet, so I figured I’d go ahead and camp my preferred fandom handle there in case it takes off.