It is archive.org. It is the domain name of Internet Archive based in San Francisco whose mission is to preserve the Internet and provide those contents for free. It is a member of International Internet Preservation Consortium and interestingly, it is designated as a library by State of California.

It basically archives the internet, and so preserves it. One other thing that it is known for is its Way back Machine. You can access the site you want on a given date. Like, if you open maemo.org and select the date you want then you can browse the site as it actually was on that date.
http://en.wikipedia.org/wiki/Internet_Archive