"That's how she rolls. Just when you least expect it, Mariska throws you a curve. Over the years, I've come to expect nothing less from the hardest working—and needless to say, hottest—perp-buster on TV." That's from the "blog" of T.V. star Mariska Hargitay, which is written solely by people who are not Mariska Hargitay (but who may know her!). "Preorder your 'XO, M' t-shirts!" reads another "blog" post. It turns out that a lot of celebrity blogs aren't blogs at all, but just...