It sounds like this is specifically for html pages, or am I assuming wrong?
Do any of these or other search engines index html content held in a MySQL
database?
Arno
It depends.. Some products are based around web spider (mnogosearch), some are only engines without spider part (lucene).
There are ways to add web spider to engine (nutch for lucene) or use only engine part of web spider (you can always generate local content [file structure] from database, it's not very clever but it works).
So the answer is yes, you can always index MySQL content somehow.
Petr