Using Email You can use email to tell people about your web site provided that the email you send is not unsolicited. You cannot and should not go buy an email list or an email directory from someone and then indiscriminately spam 10,000 people with email. You will garner nothing but ill will, and potentially legal action, if you do that.
Email is an extremely sensitive topic right now.
This has become a large problem on the Internet in the past few years. Many firms refuse any dealings with organizations that commit these actions. If an unsolicited email were sent from our systems, this could have a severe impact upon our business. Further, there has been a movement in a number of states to make this form of emailing illegal. The US Code which covers junk faxes may also be held to apply.