This is a pattern I've seen, recently. Going nutso on the sales and marketing without building up a product and a strategy to back it up first. They went far too quickly for something that hadn't proven its worth and demand yet.
Interesting article, but my comment is re. Medium's UI: they break space/page-down/page-up, due to the bar at the bottom of the page: one loses a line of text when spacing down, and then when going up a line with a cursor key, a box drops down and hides several lines. Horrible, horrible UX.