1) it was a big story in general, 2) it was a very big story in the tech blogosphere and 3) it is one of the most successful ycombinator companies to date (ycombinator also being the host of hn). Seems pretty straightforward to me.
I think it's a bit to much, too. It's essentially just one story..<p>As to why? Because it's a popular, successful startup (and an extremely awesome way to travel!!!)