Hi Steven,
It's a bit hard to know what you are actually asking. The Domino server has been serving content to the Web for seven or eight years, since version 4.5 (back when it was called the Notes server).
If you are trying to work out whether there are any advantages to running a Domino 6.5 web server over Domino 5.0.8, then the best place to start might be with the articles in LDD Today.
http://www.lotus.com/ldd/today.nsf/nd?OpenView
Specifically, there's information on the Web Server improvements in the Domino 6 server here:
http://www-10.lotus.com/ldd/today.nsf/bd92b9843c22bef685256b7d006aee6c/089a22f9f8a573af85256a1b00782950?OpenDocument#Web%20server%20enhancements
There won't be many additional improvements in 6.5, but if you are planning to upgrade from 5.0.8 then 6.5 is generally the version to move to.
Rupert Clayton
London