Torchlight is planned, but it's still in the conceptual stage.
According to Schaefer, “That’s obviously still in the plan. But is it the next thing or is it something beyond that? We just don’t know. We have a lot of good ideas for the MMO, we just aren’t committing to any kind of schedule yet.”
He added, “If Torchlight 2 blows up on PC and it’s the biggest thing since sliced bread we’ll probably want to give more attention to that before heading into the MMO world.”
It'll be interesting to see if the Torchlight goes the Diablo-to-World of Warcraft route or if it remains a Diabloesque game, only with persistent multiplayer.