I agree with the creepy angle. It's worse when you consider that FISA which Obama renewed and enhanced Christmas 2012. The US intellegance agencies can access and harvest any non-US citizen's data that happens to be stored on US company servers without warrant, notice or probable cause.
On the other hand, Google is already using all your Android related and other Google service hosted data. They already know what Google Now knows because it helps them sell ads better. The user, who's data it actually is, may as well enjoy some of the benefits the hosting company already enjoys.
If your using Android OS then using Google Now really doesn't increase your exposure.
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