Do me a quick favor. Go to gmail.com in another tab. Go ahead, I'll wait....
Serious, go there.
Okay, not look right under the username field on the page. the example for a username is 'email@example.com'. Ha. Poor Pat. Pat must receive a lot of junk mail.
After a little further exploration into this slightly random quandary I found myself in (exploration meaning that I typed example.com into my Chrome browser address bar, struck the 'Enter' key on my 104 button keyboard and waited impatiently as my overpriced, snail-paced 1.5 (0.3 in reality) Mbps internet connection retrieved the results. The results actually made me laugh. Go ahead and try it. I would bet that the results won't make you laugh like I did.
The fact is, example.com is used in about every book I've read in the past 8 years of my life (excluding those books I've read which contained plots - a small minority of my reading library) and I have never once thought to check the domain for content.
When I checked my email this evening, I noticed poor Pat's email address and wondered... what if I'm missing out on something spectacular. Boy did I get my hopes up. If you click through the one link on the resulting webpage, and scan to section 3 where the 'rules' for the example SLD, it reads simply as follows:
3. Reserved Example Second Level Domain Names
The Internet Assigned Numbers Authority (IANA) also currently has the following second level domain names reserved which can be used as examples.
So, if you were ever interested, or even if you never will be, there you have it.
FYI, SLD or second-level domain refers to the 'name' of the website as most people know it. For example, in facebook.com, 'facebook' is the second-level domain name, being the name of a company or an organization. In our same example, facebook.com, the FLD or first-level domain name is 'com' which refers to the type of company or organization (or at least that was the original intention).