Copyright information is great for this. Remember that menus, copyright information, and other secondary information should always take up as much space as possible. The sad thing is, every principle I described is one I've seen in use, on real pages. I've even had people tell me they aren't really concerned at all with whether blind people, or people with less than cable-modem bandwidth, can see their page. However, a corporate Web site can't afford to dismiss whole sections of the population so casually.
Blind spots are a big problem here.
We forget how privileged we are. Try to check your assumptions by asking people who don't have the newest computer what options they think they have. When you require a specific version of a browser, or a specific feature, you are telling all the people who don't have it, for whatever reason, that you don't want their business, you don't have anything to say to them, and you don't care. No, it isn't. Build a page that works in everything, be it Lynx, be it the so-called browser that runs on my PDA, or be it the latest and greatest version of Netscape.