Like Julia said, we're working on it. And for basic stuff, supporting IE is cake. Some of the features weren't cake and rather than release them non-functioning we made the call to get it working right. Soon!
We also decided to launch this as an experiment as well to get input and feedback like we are getting here. Rather than try to make it perfect at launch, we'll get the minimum viable product out there and see what the world wants from it. We've already made some changes and are continuing to do so based on feedback from the masses.
I understand your view point. I've done a number of projects where all of us were coders/hacks and the product didn't go anywhere. It was awesome, but, no one knew about it. This is Cindy's vision so we can't very well kick her off :-)
Currently, there are only three of us on this full time. The others are part-time and great contributors to the project. We had Pivotal Labs on board early until we could find someone like Julia to join us full time. And, for some big chunks, we'll likely get them to help out again. They are a great shop.