Wayback Machine is used so often by many of us for many reasons. Want to see the first RustyBrick Web site, use the wayback machine. But it is also used as a legal tool "to turn up old Web pages" that can be used in a legal case. Due to this, one law firm wanted to prevent this from happening and decided to bring in the Wayback Machine into a lawsuit.
This lawsuit has an incredible number of implications; to name a few: (1) The fun aspect of bringing up old versions of Web sites (2) A sure fire way to prove copyright infringement (3) Many search engines have "caching" functionality
Update: Gary Price send me a link to the full lawuit http://blog.searchenginewatch.com/blog/pdf/ia_lawsuit.pdf.