My comment didn't say that the product was useless, and it certainly didn't shit on the idea of an online storage solution. In that thread, I was saying that I already had an online storage solution, and it was working pretty well for me. When I said the notorious "quite trivially" phrase, I was in fact predicting that it would be easy for every other tech company to jump on the same boat.
Regarding USBs, Dropbox's messaging at the time was "throw out your USB drives", and this was before smartphones or ubiquitous dependable network connections. At the time, if I had to give a presentation in a university classroom, Dropbox wasn't moving the bar much on that particular problem.