I recently turn off mod_rewrite when I noticed that sometimes when going over my site my browser will show the dynamic url instead or the rewrite. My reasoning for this was that I was afraid that google would penalize me for duplicate content if it spiders a page once under the dynamic url then again later under the rewritten url. Am I right or does google see the dynamic even if the rewrite is on?
You can turn url rewrite function on without duplicate content issue by doing 301 redirect to each and every single page. It can help all cached pages in Google with old dynamic url to be replaced with the new rewritten url instead. Here is some sources I would recommend to reading out. Htaccess Mod Rewrite Examples, 301 Redirects, Dynamic URL Rewrites Setting up 301 redirects with Dynamic URLs - Stack Overflow SEOmoz | URL Rewrites and 301 Redirects - How Does It All Work?
That sounds like a real pain. If I have to redirect each page i add to my site, I think I'll just leave it off. Thanks for your help.