Search engines

[Laura B. Cohen]

Yesterday someone posted an interesting message which stated that
"any of these terms" keyword searches in Lycos and Alta Vista
made use of the weighted search capability of both services.
Can anyone point me to documentation about this, either online
or off? I'm particulary interested to know if "any of these terms"
searches are considered superior to the "all of these terms" option
available in these search engines' simple search (as opposed to power 
search) interface.

Many thanks.  -- Laura Cohen

          Laura B. Cohen
          Network Services Librarian 
          University at Albany Libraries   
          Albany, New York  12222           LCOHEN at CNSVAX.ALBANY.EDU