The just recently announced SilverlightDevCamp Seattle has been merged with the upcoming BarCamp Seattle. They were both on the same weekend and there are only so many geeks in Seattle that like to camp indoors on the weekend, so why not setup one campsite.
The advantage of this is a larger more diverse crowd. The disadvantage is following the BarCamp style of session scheduling there is no room for giving a special preference to a certain technology.
At this point, I'm just going to refer to it as "BarCamp Seattle with a possibility of Silverlight content". BCSwaPoSC still sounds like a good time and I plan on camping there for the weekend.