Well, there's a short answer and a long answer... If you don't know much about city sim games at all, you can read the long answer here. (This blog about Sim City 5 rumors also covers some background.) The short answer is that the project started as an article I wrote after the release of Cities XL; The article was really long (you can read it here, if you're interested), so rather than try to make a forum post of it I decided to start a Simtropolis blog, called The Next Generation. After thinking about the concept some more and fleshing it out on the blog, I decided it was a pretty sound idea and worth setting up a formal project. So, over the next couple months, I built this website, which was launched on January 14th, 2010.