I felt the same way when I released my todo app (http://benrhughes.com/todotxt.net - a windows implementation for http://todotxt.com). I mean, who's ever going to use this little PoS that I wrote basically so I could update my task list at work? The last thing the world needs is another todo app.

That was a bit over a year ago. Now I have ~500 active users and a half a dozen of contributors. I get random "thanks" emails, the occasional donation, and something nice to put on my resume. And the satisfaction of actually shipping something.