You could walk the site into a separate db, and then use a shell script
to examine the database for differences.
EG:
gw -dXDB -sc "select Url from html order by Url" >Xlst
gw -dYDB -sc "select Url from html order by Url" >Ylst
diff Xlst Ylst
Will produce a list of the new/removed Url's from two databases.
Diffing the actual content requires a little more effort, but
it is certainly do-able. We have a customer that uses the
Webinator and Texis together in this manner to track changes
in Bills that are before state legislatures.
Thunderstone