I wrote and contributed important code in an area (Computer Systems Integration) after seeing it lacking for years (https://github.com/mqsiuser/Generic-ESQL-Utilities). I just saw that I could do it and I figured out how and thought intensly about everything (putting in a lot of effort) and... how to benefit from it. Now the software business is not so easy: The right thing: Open Source (Almost) Everything. The problem: How to create income.

Next http://www.use-the-tree.com

Same problem. It isn't easy to monetize in IT. There are paved ways though and I'll certainly be back on a freelance consulting project soon :)

I lost my last one because I was too occupied by my side project (nevermind, the project wasn't really worth it)