dougmcc1 - 4:56 pm on Mar 27, 2010 (gmt 0)
Thanks for the great information, Jim. This is much more technical that I had assumed. I just want to prevent search engines from crawling the same pages over and over again when the content hasn't changed which is a big problem on a site with thousands of pages.
Maybe I'll just play with the meta robots tag to tell the search engines when to crawl each page instead of messing around wih if modified since/last modified in order to avoid accidentally breaking something.