ATM is Asynchronous Transfer Mode. It uses a different structure for its packet sizes and service levels. ATM isn't just for video and it is one of the technologies that saved the Internet. If you look at some diagrams of the Internet you can usually see the infamous ATM cloud where traffic goes in then gets shifted around according the ATM protocol. It is capable of handling a lot more traffic more efficiently then traditional TCP/IP... Internet backbones use ATM...
Not sure on the other stuff though... :)