I think the reason that there seems to be so many different experiences here is that IP addresses seem to be cached at various parts in systems which can include the borwser's cache.
I have just remembered the problems some people had when the Annexe was moved to a new server and new IP address. Some people got all the new site, others the old and some a mixture of both. Im my case, I had to clear all by browers' (3 of them) caches before they would constantly retrieve pages from the new IP address.
Jon