For viewers with short memories, the deep-voiced narrator in the “What Is iPad?” ad that debuted Wednesday evening on American Idol might have sounded a bit too much like a Motorola (MOT) Droid commercial (“Should a phone be pretty? Should it be a tiara-wearing digitally clueless beauty pageant queen?”)

But as several observers have pointed out — starting, we believe, with Mac Rumors‘ Arnold Kim — the reference is both older and more problematic.

The ad is actually an homage to “What Is Newton?,” the first TV commercial for Apple’s (AAPL) famously unsuccessful PDA. When Steve Jobs returned to Cupertino after his sojourn in the desert of NeXT, putting Newton out of its misery was one of the first executive decisions he made.

Some of the early reviews for the new campaign have been positive, some less so. In Apple’s defense, Get a Mac is a hard act to follow.

Below the fold: The old “What Is” and the new.

What Is iPad?

[youtube=http://www.youtube.com/watch?v=fihOmQY-JxY]

What is Newton?

[youtube=http://www.youtube.com/watch?v=Bh-yed48e0Y]

[Follow Philip Elmer-DeWitt on Twitter @philiped]