Email marketing campaigns are batch emails sent to a database of people who have "opted in" to receive email from the sender. It is very important that any list used for an email campaign follows the CAN SPAM regulations. Many sites will sell you lists of thousands of names but, if you use them in your email campaign you are breaking the law.
Have you been sending out email consistently to your customer base? Have you kept them informed of upcoming events, sales or latest news? Chances are, if you have, you have seen an improvement in your business. Are you tracking all your behinds the sceen data - how many opens, click throughs - and how many times your email is sent to a friend?
You see, email marketing does not stop when you push the "send" button. You need analytics to see what recipients do with the email. There are plenty of email marketing companies offering free or virtually free web analytics (try Constant Contact or Mail Chimp ). The stats measure your campaigns success, give you a concrete way of seeing what "speaks" to your client base and provide quality information on how to improve your campaigns.