Toombstone1881 posted a link to a comment thread with Forceful's explanation. Here is the text, to save you a click...
<forceful>
After much thought I've made the tough decision to delete my account. It's gotten to the point where making submissions is a chore. It just doesn't have the magic that it used to. Nothing to do with the people on the site or the content of what's on it. I've realized when I'm at work, I'm not really there. When I'm at home, I'm not really there. I'm thinking about my next submission. Did I use the right template? Was my grammar correct? How can I get the most points? Oh, my points. My precious virtual points. They aren't even real, they're meaningless, but I want more and more. My addictive personality perhaps. I want you all to know that you guys rock and I wish you all the best, even the people who I didn't get along with. Who knows, if we actually met, we may get along fine. So, some time tomorrow morning my account will be gone. Thanks for putting up with my shenanigans. Smile when you think of me.
</forceful>