The Wayback Machine is a website that stores old caches of other websites to act as a sort of archive of the internet. I’m sure their EULA probably discourages it, but has WM ever been used as a sort of ‘witness to the internet’ in any court cases?
Yes. The WSJ has a rather lengthy article on the subject: http://online.wsj.com/public/article/SB112242983960797010-qndezZbakQChoXkYrzRSRibbN6A_20050828.html?mod=blogs
In addition to the expected domain squatting and trademark issues it helps with, it was even used in a murder case in Canada.