Alexis and Steve applied for the first YC batch with a cell phone food idea that pg rejected.

He told them that he liked them, but not the idea. He suggested instead that they build "the front page of the Internet". They did, and the rest is history.

People have a tendency to think that phrase is somehow bragging, but it's really just what the original idea for reddit was. It's not about their size, but about the intended purpose of the site.