Speaking in ways commonly used to converse in text on the internet.
Including but not limited to; the (often unnecessary) abbreviation of words, acronyms
special characters (@,~), numbers (
l33tsp33k), *actions*, /me command, "ooc" and other RP references, emotes, ASCII, Real or Pseudo Programming Code, and HTML tags
The recent popular use of text messaging on cell phones seems to have made the shortening of words much more common than ever before.
Also:
netspeek, netsp33k, n37sp33k, and other variations.