Online communication is difficult and LiveJournal even more so in my experience. It's not just the, often mentioned, inability to judge someone's tone when you're not able to pick up on visual cues, though that's important, it's also that weird sense of public/private so you never quite know if a post was meant as a private thought or a public discussion starter and it's the combination of people you know really well, quite well and not at all trying to have discussions together and therefore soemtimes using shorthand or allusions that completely bypass some of the people in the discussion.

Also personally I use far too long sentences *stops now*