Email marketing is a simple and cost-effective promotional tool used by marketers to boost traffic, promote a direct marketing offer, announce a new product or service, build brand awareness, and increase revenues through advertising sales. While email can be a powerful marketing tool, it’s not worth doing if nobody is reading. So you should have list of subscribers before starting business email marketing. Before you send any marketing emails to an email address you have collected, you must receive permission to do so. The only way to get a group of people who want receive your email is to ask them to opt-in to your email list. An opt-in simply means that people have given explicit permission for you to email them. The opposite of opt-in, email marketing is spam. And spam is the bane of any good email marketing program. Though sales are made from spamming email addresses, your online business reputation can be harmed in the process.