The punchline to an old cartoon is "On the Internet, nobody knows you're a dog," but these days, that's no longer true. It's easier than ever for the government, Web sites and private businesses to track exactly what you do online, know where you've visited, and build up comprehensive profiles about your likes, dislikes and private habits. And with the federal government increasingly demanding online records from sites such as Google and others, your online privacy is even more endangered. But you don't need to be a victim. There are things you can do to keep your surfing habits anonymous...