That's not a failure to me, Matt. Giving up on it was, IMHO.

You don't just build something and expect people to use it. You have to get feedback from them, listen carefully and adjust your product to what the users really want. You did a splendid job on getting that initial traction and people signing up, now figure out from the users why they decided not to use it.

Keep it up, man. People want it and you have proof :)