I've had a good day cleaning up my error logs. Good deeds include:
1. creation of crossdomain.xml file
2. creation of 2 small png images that apple users use to bookmark, an apple favicon if you will...
3. sending a lot of requests for ancient php-ads files to 403 black hole
4. fixed a broken css link that didn't really do much but filled my error logs with THOUSANDS of 404s
now the big one remains:
[Mon 11 13:48:11] [xxx.xxx.xxx.xxx] Recursive include of "includes/menu.txt" in parsed file /big/dom/xex_ample/www/page.shtml
there are thousands of these too, and there doesn't seem to be anything in common either in the include files or in the page the file is included in.
I've hunted about a bit on the web and someone mentioned it might be pages being viewed locally on users' computers.