Look, advertising is a mysterious thing, okay? It takes some crazy genius can figure out how to make you want things without you even realizing that's what's happening. Any Don Draper monologue can tell you that.
But, as Rene asked, who were the geniuses who came up with this one?
Alright: devil's advocate time: We get it, time spent humanizing Bill Gates is time spent humanizing Microsoft; we even get the secret 'anti-switcher' message for hardcore Seinfeld fans who remember the Mac in his apartment. Heck: we get that Bill/Microsoft1 is a mensch and shops at regular stores for regular people, not some overpriced, all white and chrome, well-designed... you get where we're going with this.
So, like the Apple ads, we get some cute humor with a heart of gold -- it's as though Microsoft went ahead and took PC, admitted straight up he's Bill Gates himself, and then ran with it. Ok, we're a little sold that this will help people warm up Microsoft. Feeling better about Vista (or, yes, Windows Mobile2) -- not so much.
Finally, and we hesitate to even mention this, but was it really necessary to make us not only watch that little derriere-shake at the end, but anticipate and wait for it? Jerry Seinfeld: you imp you.