>What is the fire burning in the pants of your market? (And who is your target market -- you've got teachers and students and school admins, please pick one.)
WebCT and blackboard (the competition) are utterly unusable from a teacher and student perspective. I'd love to use something different if I ever have the need for more than just HTML. The main thing I'd like is a grade management system when I deal with large courses.
However, I'm almost certainly not permitted to use a grade management system besides the one my university provides, certainly not a third party one. That would violate student privacy.
Another problem is that commercial software can't (legally) add all the features of blackboard: