As I recall, even before it got to HN, he had emailed them and they did a "full restore" from a backup. I put it in quotes because it didn't fully restore the files - there were a lot missing.

I think they managed to track down most of the missing files afterwards, but it wasn't fully restored, and definitely not easily.

Again, this shouldn't dissuade you from using Dropbox. But it is most decidedly NOT a backup solution, and people don't just say that sentence for fun - it's true.