Game Informer have been chatting to Dustin Browder, lead bossman on StarCraft 2, and at the end of the interview, when asked about the other installments of the game, he said this: "We've got some mods we've developed internally that we're going to put out to get some more art into the hands of the mod makers but also provide what we hope are some polished gameplay experiences for our fans to get more value out of Battle.net."
A developer releasing its own mods? I'm not even sure what you call that. Creator generated content? Anyway, they had talked up how powerful and flexible the engine is before release, so I guess we will be able to see Blizzard put some of their own muscle behind that notion. Interesting.