Facebook will soon launch a new ad targeting option that will enable you to reach current customers based on contact information you’ve already collected.

Just to clarify, this form of ad targeting will use customer lists that you’ve already created — for example, if an individual signs up for your email list or creates a user ID on your website.

Once launched, you’ll be able to upload that list of email addresses, phone numbers, and user IDs to Facebook, where they will be compared with the social network’s user data. It’s important to note that both groups of data will be encrypted so that Facebook won’t have access to customer information, and vice versa.

From there, you’ll have the option of targeting your ads at that group, or a specific demographic within the group. For example, Amazon could market books by authors customers have already read, or tailor a message to males ages 18-25 about textbooks.

According to a Facebook spokesperson, in one early campaign, a financial services company was able to double its fan base in two weeks at a lower cost-per-fan than ever before. As TechCrunch noted, most businesses have loyal customers already, they just aren’t fans in the Facebook sense, yet.

This is something that both small businesses and large brands can take advantage of. However, we expect to see some resistance from Facebook’s user base, as the idea of more personal information being used could elicit some negative feelings.

The targeting feature will be available to all advertisers that receive support from Facebook starting next week.

[Via: TechCrunch, Image credit: Jennifer Beese]