That "those guys" may have seen the video he posted was just an unsubstantiated suspicion of his though. The sad part about having brilliant ideas for apps (as I have also found out, fortunately before putting a lot of effort into the idea) is that there are millions of other developers in the world, and one of them is almost guaranteed to have had the same idea a bit earlier than you. Unless it's a super niche thing, but then the market for it is also super tiny...