Accessible and inaccessible web pages can look very similar on graphic browsers and yet, behave very differently for people using adaptive technology. Here are a couple of examples taken from the Cal Poly Pomona home page with output from the Fire Vox "screen" reader. The images link to .mp3 audio files; the first is more than to megabytes and the second more than five, so prepare for long downloads if you have a slow connection.
The first example is the Cal Poly Pomona home page from April 2007. Below is a screen shot and a link to the sound file produced by Fire Vox [sound files coming soon]. This page is also fully navigable by the keyboard.
The second example is the Cal Poly Pomona home page from October 2003, retrieved from archive.org. The actual 2003 web page just barely met accessibility standards, so we have removed all the alternate text for images to give you an idea of what a truly inaccessible web page would sound like (the visual appearance was not affected at all by this change). Although the page is largely navigable by keyboard, there was a javascript rollover menu in the wide gold bar at the top that required a mouse. It was still accessible, though, since each of the landing pages presented the rollover navigation as static links.