No.
No, xbox users cannot play against ps3 users.
There is no way. PS3 users play on "PlayStation Network". XBox users play on "XBox Live".
No
There are about 23 million ONLINE Xbox users. The total amount of ALL the Xbox users is unknown.
No you can't do this. Unless you are using a game specifically made by Microsoft to play from a PC with Xbox live users. (EG: shadowrun)
Yes. Look up" Black; the game for xbox 360.''
because its on xbox 360 not xbox
No
Yes. The Xbox 360 allows users to watch DVD's on there xbox.
Currently, Microsoft Kinect can not be used to play Call of Duty: Black Ops, however, you need an Xbox 360 to use kinect and Call of Duty: Black Ops is playable on Xbox 360 (Assuming you have an Xbox 360 version of the game)
you can play online with xbox 360 and the PC. There are also other systems, but the Playstation Network or Xbox live is on the internet and not actually online gaming which Black Ops does not have.
XBL stands for Xbox Live, and is Microsoft's online service that allows xbox users to play games online and download content from the marketplace.