KNOW Web browsing can leave a trail. Organizations keep a log of your browsing path and can disclose it without your knowledge. Websites can even determine which pages were viewed and which were not. If a site's logs were raided, your address, and accordingly, your identity would be exposed. Registration information at web sites can be collected and sold to any number of database services that can, with other information collected elsewhere, be compiled to create an eerily accurate individual profile.
Email is like a postcard.
Because a message is sent to a server before being forwarded to you by your Internet Service Provider, people with access to that system can read any mail you send and receive without having access to your computer or your password. Read the CNN article . Newsgroups archive postings. Internet users all over the world can easily access anything you post to newsgroups. Messages you casually throw off to friends are stored and could be retrieved years from now, out of date, out of context and regarded as a representation of you and your opinions.