My name is Jan Biniok, I'm the author of Tampermonkey.
I started working on Tampermonkey in May 2010, it emerged from a Greasemonkey userscript that should be wrapped to work as a Chrome extension. After this was done I had the idea to re-use parts of that code to write a script manager that provides more Greasemonkey compatibility than Chrome's native script support.
From there it grew as I added more options and functionality. I got a lot of feedback and more ideas, and kept building.
Please help me to offset the development time, server expense, etc. and donate a small amount.