??? It wasn't until 9 months ago when Ev Williams changed it to a writers' platform. Before that, it was promoted as a place where readers could find wonderful articles.
The readers have been fleeing these last few years, though. So Ev had to do something. So he chose to cater to writers - there are a lot more writers than readers.
I think it's total bullshit that one can learn to 'write' after one has left school. If one hasn't achieved a publishable standard of literacy by the time one leaves school, then I don't think there's any hope.