Very interesting, but something was missing from this essay.
I was a college student from 1988 to 1992 and had a student UNIX account on the schools computers with access to USENET and IRC. Both of these took up too much of my time. Of course, now I’m typing a message here; I guess some things never change.
Anyway, I was exposed to a much less sophisticated version of l33tsp33k, and I don’t even recall the term being used at the time. But my impression reading postings and participating in chats of the time was the overriding fear of computerized monitoring of the communication channel is what drove the deliberate obfuscation. If you wanted to talk about a topic that would have caused LBJ to open a file on you, it was considered prudent to be oblique.
So a discussion of 53x or //33d or “The @ncharists c00kb00k” would help prevent the dreaded TLA agencies (FBI, CIA, NSA) from automatically identifying you as a some kind of subversive. The tactics I saw were deliberate misspellings and acronyms in addition to the character substitutions described in The Straight Dope’s article.
Another force for typographic creativity was the signature file on USENET and email of the time. It is still with us today, but either the creativity that goes into it today has diminished, or my friends have gotten more staid. Character art was a big part of the signature files (dot-sigs for short) at the time. I think it was helped along by the uniformity of the character set of the time and the lack of a graphic outlet in the new electronic medium. I remember sending a girlfriend a dozen electronic roses:
@-,-’-,- @-,-’-,- @-,-’-,- @-,-’-,-
@-,-’-,- @-,-’-,- @-,-’-,- @-,-’-,-
@-,-’-,- @-,-’-,- @-,-’-,- @-,-’-,-
and they were very well received!