Both free and commercial Webinator maintain an index on Title\Meta\Body .
They wouldn't be able to search otherwise.
The first time -index is used (either specifically or automatically
at the end of a walk without the -noindex option) it creates 4 indices:
"create metamorph inverted index xhtmlbod on html(Title\Meta\Body);"
"create index xrefsurl on refs(Url);"
"create index xrefsref on refs(Ref);"
"create index xhtmlid on html(id);"
Once created, the 3 regular indices are self maintaining. The
metamorph index needs to be updated to reflect inserted/deleted
records. On subsequent usages, -index will update the metamorph index
(not rebuild the whole thing). During the index update there must be
sufficient disk space for 2 copies of the index.
-k settings are applied when the index is first created, and can not
be changed on subsequent updates without first dropping the index.
-unindex drops all of the indices created with -index.
(and forgets the -k settings)