Many people have no idea how much of a two way process the web can be.
Yes, they know they can send credit card details, meet in chatrooms, post messages in newsgroups. But, what most users don't realise, is how much information is being exchanged without their concious consent. How many precautions you take is up to you. Click on the anonymous button above and you'll find out how to easily vanish into cyberspace, or carry on surfing as you did before, but maybe with a little more awareness and a couple of browser tweaks. There's plenty more available, of varying degrees of usefulness to inquisitive eyes.