Archive.org should be high on any list of important research Websites. Essentially the people behind this site are attempting to capture the history of the Internet and the data that has been posted there, even after the data has been removed. You can read more details about that mission here. One part of that effort is the Wayback Machine, which has older, outdated images of Web pages dating back to 1996, about 40 billion total. It is a great way to view discontinued versions of web pages and has already been used in court proceedings. They’ve recently been sued by another company over the Wayback Machine. There’s some extensive commentary over the suit on the Patry Copyright Blog, if you have an interest. Oh, and if the name Wayback Machine rings a vague and distant bell for you, click here.