Technology Review has an article about an Adobe project named Zoetrope which promises to give users access to web content through time. It’s a little hard to explain, but essentially it allow you to scroll back and forth through a time-line and look at pages or parts thereof over time.

http://uk.youtube.com/watch?v=7C-B7qdClak

It has the makings of a very powerful tool, with the only downsides being its requiring a huge amount of historical data (such as that stored by the Internet Archive), and very fast access to same (which the Internet Archive doesn’t really provide)