Facebook has tried many different ways to get advertising and the social network to mix, and now, the company wants more credit for generating online sales. Facebook will begin rolling out a new tool that will allow online retailers to track purchases by Facebook users who have viewed their ads.

"Measuring ad effectiveness and outcomes is absolutely crucial to all types of businesses and marketers," said David Baser, a product manager for Facebook's ads business who said the "conversion measurement" tool has been a top customer request for a long time. The conversion tool is specifically designed for so-called direct response marketers, such as online retailers and travel websites that advertise with the goal of gaining immediate sales rather than long-term brand building.

Online retailer Fab.com, which has tested Facebook's new service, was able to reduce its cost per new customer acquisition by 39 percent when it served ads to consumers deemed most likely to convert, Facebook said. Facebook defines a conversion as anything from a completed sale, to a consumer taking another desired action on a website, such as registering for a newsletter.

Marketers will also have the option to aim their ads at segments of Facebook's audience with similar attributes to consumers that have responded well to a particular ad in the past, Baser said.

Facebook has also expanded its physical gifts market, widening to include tens of millions more users and pulling in new retail partners as its sellers, including babyGap, Brookstone, Dean & Deluca, L’Occitane, Lindst and NARS Cosmetics.

NARS Cosmetics recently launched a campaign to let users make over their Facebook profile, ala Andy Warhol. Its limited-edition product line for the holidays is inspired by Warhol, so the company created the NARS Profile Makeover app, which allows users to “Warholize” their Facebook profile for a visual makeover.