I am not an expert, but I will do my best. Metastreaming is the process where a user can view and rotate a Metastream object in real time with small downloads, much like QuickTime VR. With certain Metacreations products,Carrara, Poser, Canoma, and Bryce, you would be able to create files that could be viewed by anyone with the proper plug-in. At the beginning of this year, Metacreations dumped their entire product line in favor of Metastream. I guess they are still in the development stage for the Mac for Metasteam 3 since nary a word has been heard about it. It is primarily supposed to be for E-Commerce I guess, and not available for the average artist like Metastream 2 was. Like I said, I am not an expert on the subject. For more detailed info check out metastream.com