Here is an interesting presentation about Memento, a project that seeks to add a temporal dimension to searching the internet. From the abstract:
Remnants of the past Web are available, and there are many efforts ongoing to archive even more Web content. It's just that the past Web is not as readily accessible as today's. For example, if you want to see an archived version of http://cnn.com, you can go to the Internet Archive's Wayback Machine and search for it there. Or if you want to see an old version of the Wikipedia page about—say—clocks, you can go to the current page and from there follow a link to one of the many prior versions. And, if you are interested in stories that featured on the BBC news site on your last year's birthday, you can explore the archive that Matthew Somerville set up in his spare time.
But doesn't doing so feel more like walking to a library, than using the Web the way you usually do? Wouldn't it be much easier if … you could activate a time machine in your browser or bot?