Earlier quoted context omitted.
Corroborating. It goes way back to the early 90s IRC and MUD cultures, from which many of us sprung. Limor came to the scene a bit later, but the culture was well-established. Most of us would code shift when writing in other milieux, some weaned ourselves off the habit when our work started interfacing with nonreceptive readers, and a few retained the affectation to make a statement (or an anti-statement!). It's amu…
> early 90s IRC and MUD cultures It goes back before that. There were well known Usenet folks who adhered to the style. The 1970s-and-earlier Arpanet was before my time, but I'm sure it existed then too ;).
I was a bit post-Great Renaming into well post-Eternal September. And we may have followed different groups.
The style arises spontaneously in isolated individuals and groups of course (at least since e. e. cummings!), but it was pervasive-to-universal on IRC and MUDs.
I do wonder how it trickled into there though. The most boring answer is probably the correct one. it was slightly easier to type and kids are naturally flexible.