The 'wayback machine' at http://www.archive.org/ allows you to see the actual history and development of a website. The site tracks webpages and allows you to see the older versions - right back to 1996.
This can be a useful tool if you want to see how long a site has been around for. It obviously doesn't work perfectly - it tries to load images from the current website url, so if a site has changed dramatically most of the graphics won't be visible. I'm sure things like this will become more useful in the future - especially as the British Library is also keen on keeping records on digital content. Might also help us overcome problems of outdated technology.
Anyway - try it out - type in a website you know and literally track its history - the larger sites work best. Also remember it isn't always accurate as some sites redirect you to other places once you are at their main url.