I'm not sure. I've mentioned it a couple of times on HN to see if anyone from Twitter could confirm or deny my suspicious. It's possible someone just rejected it themselves but I'd really like to know.
Come to think of it, I know of several examples(startups) where the company was actually failing and about to run out of money and they still advertised but couldn't possibly hire. In my opinion, that's purposefully wasting people's time.
ANd yes, it is a huge waste of time.