Via his personal blog, Nebraska farmboy turned Twitter co-founder Evan Williams (that's @ev to you) announced plans to leave the, ahem, microblogging service. He writes:

After stepping down from CEO six months ago, my mind started to wander. The reason I left Blogger/Google when I did is that I felt it had reached a place where it was on solid ground and in capable hands (at the time, Jason Goldman’s as product manager). Though still an independent company, I realized Twitter may be at a similar point today. So, as was reported in various places yesterday, I've decided to scale back my role at the company. (I'm still involved, but it's no longer my full-time job.)

What's next for Williams? Only he knows. "I’m not ready to talk about what I have planned next," Williams teases, "but I will venture a prediction about what's next for Twitter: It will be bigger and better."

Williams will remain on the board of directors of Twitter and, presumably, grab a veggie $5 footlong at the Twitter headquarters building's Subway on the rarest of occasions.