Very fine-grained details can be specified in the URL. "URLs are the command lines of the 21st century" (or something like that). Yes, the following look like "URLs from hell," but no one would actually type these in. On the other hand, they don't necessarily have to come out of a form on an HTML page. A program can generate them. Thus, URLs are pointers/handles to data. Think of the web as a huge associate array (hash table), with URLs as the keys (indicies into the table), and the corresponding HTML (usually generated by a CGI program) as the values.
Directions Fairmont Hotel to O'Reilly: http://www.zip2.com/scripts/map.dll?type=jdir&sType=street&dType=street&dType=street& dstreet=103+MORRIS+ST&dcity=SEBASTOPOL&dstate=CA&streetaddr=N+1st+St&userid=1184558& userpw=xtv0J_txAwt8tE_FD0C&version=91450&java=no&sType=street&streetaddr=1st+st.& city=san+jose&state=CA&ccity=SEBASTOPOL&cstate=CA&ck=3599047&adrVer=872139786&ver=d3.0
That graphics can be generated on the fly on one machine, and then embedded in a document located on another machine, is an excellent illustration of how the web provides distribution computation and compound documents: accessible with a single line of code: an <IMG SRC> tag where SRC= points to a full (not relative) URL.
Interactive map of O'Reilly: http://www.zip2.com/scripts/map.dll?type=ams&a.v=1.0&a.zl=7&a.c=a&a.z=0&a.w=350&a.h=250& a.i0.t=a&a.i0.lk=&a.i0.sr=103+Morris+St&a.i0.ct=SEBASTOPOL&a.i0.st=CA&a.i0.id=242& a.i0.lb=End&a.ic=1&a.ct=1