What year did Apple introduce the iPad?

Steve Jobs was really good at introducing things — besides, maybe, possibly, the iPad.

I remember it getting pretty much panned by everyone I knew when it was first announced. It wasn't really clear what it was, or why you needed it. Flash forward to today, and those same friends have 18 of them (more or less).

Like many of the things Apple does, they revolutionized the market with the iPad, creating an entirely new type of device we now just call "tablets" — which, I have to say, is a bit better than calling them "pads".

But when did the iPad first get introduced?