I can't access the site from work; is there any information about sharing character files with one another? As a DM, I like to have my players' character files available so I can see what magic items they might need, etc.
According to the faq, as of launch date, no (there won't be an export function) but they understand this is important to us, so they're working on it as quickly as possible.
Silverlight? Ugh. Well, the good news is more people should be able to use DDI now. The bad is I can't use CB off line any longer, which isn't imperative for me, but I know several people who would bring their laptops to the meetup events who aren't going to be very happy.
Questions I am hoping to see answered: Can you have house rules with it? Can you still export your characters? This has the potential to kill a lot of third party tools out there.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.