I've been reading a lot of (work/technical) books and online documents recently that use example.com as their example domain name. I wondered whether someone owned it, and if so, how much money they were making from advertising to schmucks who try and use the examples in the books. So I went for a look, and found:
You have reached this web page by typing "example.com", "example.net", or "example.org" into your web browser.
These domain names are reserved for use in documentation and are not available for registration. See RFC 2606, Section 3.
It reminded me that the internet has a venerable history as a research network, and it's only been just over 10 years that people have been doing anything commercial with it at all....