Experiment (YC W13) started off as a Show HN, but back then we were called Microryza. It was a very modest thing, and after somehow getting near the top of the front page, we were flooded with traffic [http://i.imgur.com/miMyx7x.png]. That traffic spike is what convinced us to quit our jobs and go all out. Show HN is definitely my favorite part of hacker news.
https://news.ycombinator.com/item?id=3833393