I’ve had the problem for a really long time, but never found a solution. For some reason it’s hard to explain, but here goes!
Okay, when testing websites and stuff, I refresh them a lot. Sometimes it gets to the point where the page doesn’t update anymore. Like, I can only see one of the old copies of the page, even when it’s on the web, not on my local machine. But, if I use a proxy server like pagewash.com and go to the website, it works.
It’s really frustrating especially when I’m testing something then it stops updating the site so I think I didn’t fix it when I really did. Anyway, I figured it was the cache or something, but I try emptying it and it doesn’t work. The problem even persists through different browsers. I am on a Mac.
The question is "Where?" There are a number of places between your computer and the website’s server.
Firefox is pretty good at not caching a site (shift + refresh will clear a cache, anyway).
If it’s not that, it’s probably your internet provider. Your only real solution (that I know) is to set up your computer’s DNS to go through OpenDNS. (There’s a free version.)
It’s awesome, but can act weird for odd non-normal internet connections…