Great CRM software or marketing automation can only go so far without a well-built email marketing database, and email marketing expert Tal Nathan writes on ClickZ that lists face challenges such as spam complaints, undeliverable addresses and more every day. He said there are ways marketing executives can grow lists sensibly and see success.

Nathan said businesses should frequently use their website to have sign up opportunities for email, capture email addresses in the real world and at call centers, find people who will refer friends and leverage social media to enhance their lists.

"As an email marketer, you've probably been required to promote your company's Facebook fan page," Nathan said. "It's a great idea, and it's time that your social media counterpart reciprocates with kindness. In addition to featuring your email registration prominently on your fan page, you can also ask them to periodically post an appeal to sign up, whether out of the goodness of their hearts or in return for some benefit."

The Small Company Blog said small business marketing professionals should remember to be ethical as well when growing a list, by doing things such as trading knowledge for contact information, encouraging emails to be passed along and assigning someone to clear inactive recipients from the list.