[Please fill in text and pointers to pages that describe what the internet is on this page].
http://www.w3.org/ is the home page for the WWW aka World Wide Web, a tiny piece of the internet. http://www.internet.com/ is a portal covering internet news, etc.
Oh well... RS sometimes has the pungent notion that the internet is composed of two parts: first, the Tcl'ers Wiki here; second, the Rest Of Internet ;-)
See also Data structures: from the bit to the Web