Viewing HTML sourcecode and figuring out how the developer implemented stuff is a common technique used by web developers to learn new things. Apparently this guy did not stop there. He was curious how HTTP headers were implemented in the wild.
At the beginning of every server response on the web using the HTTP protocol, there’s a bit of text like the following. These headers are not usually visible by web browers.
HTTP/1.1 200 OK Content-Type: text/html Connection: close
His analysis from 2.6 Million server response had an interesting outcome:
Mickey-Mouse: Does_Not_Live_Here
Limerick: There was a young fellow named Fisher Limerick: Who was fishing for fish in a fissure, Limerick: When a cod, with a grin, Limerick: Pulled the fisherman in Limerick: Now they're fishing the fissure for Fisher.
X-You-Are-Owned-By: morris X-Thank-You: for bothering to look at my HTTP headers X-Answer: 42
To top it off, this guy added the following comment in the HTML source to invite developers looking at his HTML source to send him their resume 
Good marketing pal.
If you're looking at our HTML source, you're exactly the person who should send us your resume. We recently redesigned our site; Tell us all about how you would make it better and better yet, if you have an illustrious career of web-hacking, drop us an email at jobs@tellme.com.
