search engine switcheroo

I'm running Netscape 3.01 on a Mac PowerPC. Sometimes when I type just
"altavista" in the location or "Go to:" field, instead of
www.altavista.com, www.webdirectory.com appears. It bills itself as
"Earth's Biggest Environment Search Engine." Can anyone else duplicate
this result? When I type "altavista" again or "www.altavista.com", the
real Alta Vista appears.  What gives? Sneaky DNS aliasing from completing
search engine company?  webdirectory.com's IP address is
and altavista.com's is