Earlier this month, Facebook introduced objective-based ad buying, giving businesses an easier way to buy Facebook Ads based on objectives that matter to them. Now advertisers will also be able to target only their customers with the expansion of Custom Audiences.

Launched last year, Custom Audiences lets marketers use their current customer list and display ads to just those people on the social network. According to Facebook, thousands of advertisers already use this targeting option in their campaigns.

Now this option is being made available to businesses of every size in any Facebook ad interface. Previously, the feature was only available through the company’s API and Power Editor tool. Small businesses in particular will benefit from this expansion.

With Custom Audiences and objective-based ad buying, businesses can message existing customers with promotions. For example, a local auto dealer can reach people who bought a car a year ago with an ad for a free oil change. You can also find new customers in a specific area by excluding existing customers from campaigns.

The feature began rolling out in all ad interfaces yesterday for a limited number of U.S. advertisers. A global rollout will begin next week, with all advertisers worldwide having access by the end of November.

To get started with Custom Audiences just upload customer email lists or a MailChimp list. Once contacts have been uploaded, you can target matched individuals with ads for your Facebook Page, website, or mobile app.

[Via: Inside Facebook, Image credit: Robert Scoble]