Making an Open Source Application More Successful?

morphex asks: "I've written an application for information and task management called the Issue Dealer that has hundreds of users, many of them very satisfied with how it works. However, new user growth has been slow, and there's not much of a community surrounding it. What can I do to encourage wider use of the application, and what can I do to get more developers interested in development and bugfixing? In short, what's missing in this picture to make it an Open Source success story?"