Instead of struggling and striving to get NEW customers, it’s best to first focus on your existing customers and nurture them to buy more from you.
Facebook’s custom audiences enables you to upload personally identifiable information (such as an email address or cell phone) and target Facebook advertisements to the contacts in your list.
Twitter has this feature as well, Tailored Audiences, announced in a December blog post. Companies such as Mailchimp have integrated with Twitter to enable you to seamlessly leverage email addresses in your database to reach these same contacts through Twitter.
Sounds simple, but it’s darn powerful.