The Internet abbreviations started because of the need to keep communications as short as possible when dialup connection was slow and keeping text lengths down was more important than it is today. I use a few of them still, mainly because they save me time when typing, and I figure most people know the ones I use. Txt abbrevs started for similar reasons on cellphones.

That said, I used some abbreviations in internal office emails even before I had access to the Internet, such as m8 for mate. I wasn't aware of their use elsewhere at the time. It would be difficult to pinpoint when any of the commonly used ones started, or who invented them. I could claim to have 'invented' (e.g.) m8 but I know others invented it independently (not that it takes any brains to do that).

To the original GUEST,Jim: RTFM ;-) (note the emoticon!)