So you do. That's pretty much how Linux came into existence. Linus Torvalds wrote the first Linux kernel for his own use and then stuck it out on the net thinking that others might have a use for it. Linux has evolved from there as people have added to Linux for their own benefit and then released the enhancements for everyone to use. I've over-simplified the model of course.
Reality is a lot more complicated but the basic philosophy still holds.
This development model works for two reasons. First, targeting yourself as the first customer is good, cheap market research. Second, the Internet provides a cheap way to announce and distribute software. Software Testing . Even if you can't tell the difference between C code and Hebrew text you can still participate in the software development process as a tester.