The Internet is mainly just another way of doing things more efficiently and quicker. Yes, that's pretty accurate. One way to avoid having info online is to limit to whom you give that info. I agree with Angel, it was very frustrating for me to find out my unlisted phone number was publicly listed on the Internet. There are a lot of businesses that sell your info, a good place to find out is to check out websites of privacy rights organizations.
Chain letters are illegal in every form.
Chain letters are a type of spam as well. Send it to the complaint dept for the ISP that the chain letter came from. If someone is truly stalking you, you need to contact your local police. There are means to track people open to law enforcement, but not to the public. There is an internship once you're in college, some local police departments have explorer clubs.