My recollection of Drew's YC app was that it was posted on HN before he applied to YC and it received wide acclaim, so I went and Googled it:

http://news.ycombinator.com/item?id=8863

Turns out my memory was only half right. DropBox had many people that loved the idea and thought it would revolutionize filesharing. It also had a large number of people who pointed out all the reasons why it wouldn't work.

I wonder if there's a lesson here in that good ideas that seem bad tend to be highly polarizing. I've recalled Paul Buchheit say here that GMail met a lot of internal resistance, with many Googlers saying it was a distraction and would never work. I also recall Larry saying that there was significant support for GMail at all levels of the company, going up to the founders, and many Googlers loved it.