I believe YikYak is based on threads/comments right? The main difference is that my app is more like one big local chatbox.

The initial idea was to achieve the atmosphere we used to have in (Dutch) public transport. Everyone could participate/listen to a couple of public conversations being held.

> one big local chatbox.

If you are within the range of one user, who is having a conversation with someone in their range but not in yours, will you only see one side of their conversation?

Like Powow http://powow.info/ (also based in Netherlands)?

You say public transport, but I have my doubts it'll work particularly well on the subway.

I think that was the inspiration rather than the goal. That's how I interpreted that comment.