I think they're being a little silly. If you use a relatively mainstream word from the language in which you do business (and which happens to be virtually identical in all languages anywhere near where you do do business), you don't (shouldn't) have a leg to stand on, IMO. You can't reasonably arrive at Dropboxe independently. But is everyone at Dropbox really supposed to tip-toe around being careful not to name a project after a common word if it's pronounced the same as a company that was accepted to a tech incubator just 2 years ago?