Notch has mentioned on his blog that he'll be handing over the Minecraft design reigns to Jens Bergensten, the Mojang developer who has been working alongside Notch on Minecraft for the last year. "He will have the final say in all design decisions, so he will kinda sorta become my boss," says Notch. "I've promised him to not pull rank. ;)"
That doesn't mean Notch is leaving. He's planning to have a bit of a rest after years of solid development on Minecraft, which was finally released a few weeks ago at Minecon in Vegas. "Personally, I will now rest for a while, then get back to work refreshed and eager. I'll be helping out with Minecraft, of course, but also starting work on some new project," he says.
Minecraft's still set to grow, with plenty of new updates and features, but it'll be interesting to see what Notch does next. Whatever it is, it'll be very highly anticipated after the extraordinary success of Minecraft, which just sold its 4,216,379th copy.