One take is that it was a bit of a cock-up on their PR departments part to release such a key business announcement on April 1st, which led to discussions on Slashdot, Webmasterworld and elsewhere on whether this was actually an April Fool that had got out of hand.
"Google said it would use automated technology to scan the content of incoming e-mail for keywords and place related text ads inside the mail"
Chris Hoofnagle of the Electronic Privacy Information Center is already on the case about that:
"It's absurd that using a communications medium should subject one to privacy-invasive advertising. Why not put an operator on the phone to listen to your conversation and pitch things to you while you're talking? You'd say that's ridiculous. Well, this is ridiculous."