You made a valid point about building in vacuum, that's exactly what I was doing with one of my projects last year and was wondering why I couldn't get any user

You made a valid point about building in vacuum, that's exactly what I was doing with one of my projects last year and was wondering why I couldn't get any users who were sticking around. Sometimes, it can be the painfully bad UI but when that's not an issue either, you know, it's probably the problem you picked to work on itself. So I'm assuming, before working on anything that you think might make some money or be useful to others, there always has to be some form of idea validation. Nevertheless, what about the developers who don't have extensive developer networks nor the budget ( think : high school student or a 30 year old who can't convince colleagues to just quit their jobs and start working full-time with them ) but great ideas, which let's assume pass the Mom test. What do they do to get the word out for developers to start working with them, after all?