Given Heisenberg's eponymous principle (or would that be the principle of the eponymous Heisenberg? No matter), and also given the fact that, from viewing my profile, you can directly observe the speed at which I post, it stands to reason that you can't know where I am.
That being said, even if this isn't the last post I can just claim that I'm not here and post again. The obvious paradox can be easily cleared up: if one of my posts is the last one, you might claim that, given I am not here, it doesn't count. Unfortunately for you, however, if we assume that I'm not here, any claims I may have made about not being here are rendered null and void, thereby proving my presence. I am Schrodinger's Troll.
Love may be blind, but lust has x-ray vision.
Avatar shamelessly plucked from PMOG.
Also, it turns out I'm not dead--I'm just a right bastard who disappears from the internet for months at a time every so often.