Msg#: 4652150 posted 3:06 am on Mar 8, 2014 (gmt 0)
Is it too late to change your URLs? Different thread.
About the ISP: Certain providers, naming no names, are notorious for caching material long past its expiration date. (Also for caching things that should never have been cached in the first place, but that's a different issue.) So your request never even reaches the server; the 304 comes from the ISP. Try fetching the page from a different computer using a different ISP. That's in addition to, not instead of, the usual empty-the-cache and force-a-refresh angles.