[lapetitejort]

...I have a coworker who starts nearly every sentence thus so, as if continuing from the last sentence, even if you haven't talked to him in a few days.

[djur]

Someone I converse with regularly online has a tendency to do this in a way that strongly conveys "your idiocy has left me speechless" in contexts where he seems to (or at least claims to) only intend "your position is surprising".

[WhyCause]

I use the ellipsis at the start of an IM sentence primarily when I've accidentally hit enter mid-thought.