Yeah, some sites apparently have the ability to hide them on their list of who's online, but they're pretty much everywhere.
"To reach beyond fear and danger we must sharpen and widen our vision. We have to pierce through the deceptions that lull us into a comfortable complacency, to take a straight look down into the depths of our existence, without turning away uneasily or running after distractions." -- Bhikkhu Bodhi
"No man ever steps in the same river twice, for it's not the same river and he's not the same man." -- Heraclitus