Well, I did. But lately I haven't had much time at all to give to it, so it's become run-down and nothing like it was before.
Anyway, it's hard for me to give the amount of time that it took. It was one of my first, major projects with PHP. I started small, just making the basic systems - messaging, stats, battling, etc. Slowly I built more on top of everything, and eventually I had a full-fledged game.
Probably the best advice I can give is to use functions and functions and function and functions. If you do the same or similar thing in more than one place, use a function. No question about it. I can't tell you how many times I changed something in my game, and had to go back and change it every single time that I had used the same or similar code. Using functions from the beginning saves a huge headache.