Sort of, I guess? In real life it's more a case of "I'm not shy, I just don't want to talk to you, so go away." really. Social interaction exhausts me and I derive no benefit from it; it's always banal and depressing.
Online, I kinda vary depending on my mood. I wouldn't say I was shy, more than I'm aware I am best sampled in extremely small doses and that most people wouldn't welcome an extended conversation with me because I have a tendency to textwall the hell out of them. Most of the time that stops me from contacting people, but there are very rare instances where I'll throw caution to the wind and take the initiative. Like, the planets aligning happens more often than that does. I don't think I'm a nuisance, I know I'm a nuisance. I don't much care, but I don't like trying to force conversation upon others. So I don't. Usually.