A while ago, a bunch of UIUC students released a proof-of-concept called Trailblazer. There history model is amazing and it would be great if implemented in Omniweb.
http://www.acm.uiuc.edu/macwarriors/...s/trailblazer/
http://www.acm.uiuc.edu/macwarriors/...s/trailblazer/