I recently looked at the "chart" of plug ins compatible with WP 2.1 and I did not see the Multiply plug in mentioned anywhere. This plug in allows WP users to have multiple blogs run off of a single install of WP. This allows each blof to function independently of the others and allows you to make a custom theme for each blog. it is great.
If you want to see what I am talking about, take a trip on over to http://www.eternalsky.us
Also, if this plug in will not be compatible with Wp 2.1, can the development team work on such a thing and make the function capable of importing multiple databses from having used the Multiply plug in?