Ok. So at this point a couple things have occurred to me.
Post it, what I think of it, as a product, will be a blogging platform. Not a social platform.
Posting quickly and easily will need to remain a top principle of the product. This should drive priority when thinking about new features.
The difference maker is clearly the idea and implementation of activity tracking. Not just a post a day. Maybe a word or char count a day. It doesn’t have to be one big monster post. It could be a flurry of small sharp posts. Like Scripting News or Daringfirball, it’s not always 500 plus words a day. Something it’s a link to an article and then short single effective quip, other time is commentary on current events. Either way this is going to influence how activity is developed.