Honestly, this is disappointing. It looks like pretty much a forum system. Nothing really special.
Yeah, users that see your activity in a community may be brought back to your blog, but you're basically creating new original content for that community. Sounds like a pain in the ass.
I don't wanna spend hours creating content for a community. I wanna put that content on my blog.
RE: A look at Steemit Communities, aka "Subreddits"