There are other forms of caching that occur too, but one of the more popular ones that isn't listed at the site is through a proxy. You also have local firewalls that have caching mechanisms built in, but there are many places where cached versions occur. I would also add that just because a browser says its cleared its cache does not make it true, especially since there are a lot of bugs that have been opened around that topic alone. Finally, I would not say any browser is better for web design, since you should build for your users and the major browsers right now are IE/FF/Safari/Chrome. Opera, while a nice browser, is used by few when compared to the entire population. Now, if your community which you are trying to reach use primarily Opera, then so be it. From a personal perspective, I try to design for all browsers; however, I use FF as my debugging browser.