When coming up with email lists or mailing lists that are to be used for email marketing, online business directories come in handy. They have so many addresses and huge databases of contacts that one can use for marketing purposes. The directories are organized into categories or depending on the business industries. This makes it easier for one creating email lists or mailing lists to choose the right addresses to include because, for mailing lists or business email lists to be effective the addresses included must be of those who are likely to sign up for the services or products that are being sold.