No sooner did AltaVista Co announce that its real-time text and voice instant messaging (IM) system would interoperate with those of America Online (AOL) Inc and the Microsoft Network (MSN) than AOL, that sworn enemy to IM interoperability, disabled AltaVista’s software on its network. James Anderson, head of the launch team for AltaVista Messenger, says he’s not fazed by AOL’s IM-blocking antics. For one thing, AltaVista Messenger is based on Tribal Voice Inc’s Powwow software, which means its users can still talk to those of other Powwow licensees, AT&T WorldNet and Freeserve, as well as to users of MSN Messenger. For another thing, Anderson believes the Powwow software can stand on its own merits. Our position as AltaVista on this is that we see the Tribal Voice IM product as a great product in and of its own right, he told ComputerWire. Interoperability is only one element of that. Finally, he believes that while AOL may prevail in skirmishes such as this one, proprietary standards on an open internet are likely to lose the war. AOL is playing a pretty dicey game here, Anderson concluded.