Cosmetics is a multi-billion dollar industry worldwide and companies that sell them have begun using Facebook to market directly to customers, offering special deals to people in different countries as well as videos tips on how to use their products and contests associated with new merchandise.

The industry is directed almost exclusively to women — and women, as we reported earlier this month, comprise more than 56% of the U.S.’s 103 million monthly active Facebook users. Here, we review nine different brands in an effort to gain insight on how this industry is using Facebook across social and economic levels to sell makeup to women — from cosmetics available at the corner drug store to higher end brands sold in department stores.

The brands we examined, in order of the approximate number of fans: MAC Cosmetics, about 404,000; Sephora, 382,000; L’Oreal, about 216,000; Cover Girl, 152,000; Avon, 90,000; Avon’s Mark brand, 86,000; Clinique, 72,000; Mary Kay, almost 62,000 and Maybelline, 24,000. Avon, Mark and May Kay are generally sold by representatives to consumers, while MAC, Sephora and Clinique are usually sold in department stores or malls and L’Oreal, Cover Girl and Maybelline are widely available in drug stores.

Overall, the pages had many characteristics in common. Imagery was decidedly “girly,” with most pages using a lot of pink, for example. Walls were filled with feedback from Facebook users and Status Updates/Posts about company products. Contests were promoted, some exclusive to Facebook users, as were new products.

But, most of the brands we looked at have not yet create a presence on Facebook that is markedly different from their web sites. In other words, Facebook appears to simply be an extension of the company’s campaign, not a unique opportunity to intimately market their products to their Facebook fans.

One notable exception is Mark, Avon’s line of products sold by younger women for younger women. In addition to Mark representatives and customers sharing tips, reviews and questions, a Facebook store full of Mark products is available on the Shop tab.

Visitors to the site may shop for Mark products — makeup, fragrances, skin care, jewelry or fashion accessories — directly on the Facebook page, without having to visit Mark’s web site. Opening stores directly on Facebook pages is a not a new tactic, but Mark’s version is very easy to use and by asking for contact and shipping information, paves the way to retain Facebook buyers and future customers.

While no other Pages currently contain online stores, a few do offer Facebook-specific promotions.

Sephora blasts a Facebook-only offer directly on its welcome page – the Offers tab — of $25 off an eyelash enhancer and then directs fans who click to their site for the purchase; the company’s Facebook page was also part of a fan giveaway during the Christmas season. Another interactive feature of Sephora’s Facebook Page is the Mobile Review box on the home page asking users to enter product information to contribute a review.

MAC Cosmetics, Maybelline and Clinique have taken another approach to engaging their Facebook audience by offering apps that fans may use to spread the word about their products to their friends. MAC’s Beauty Marks, Maybelline’s Kiss and Tell and Clinique’s Share the Luck are gift apps that allow users to send company-themed gifts to friends and then publish the fact to their news feeds. Clinique has a second app, Lucky Day Sweepstakes, inviting Facebook users to enter to win the company’s newest lip gloss.

L’Oreal’s Facebook page is the only one of the bunch that is actively promoting products for men — a January 20 status update stating, “L’Oreal Paris USA  Can’t ignore the guys!” and plugging an eye roller to abate dark circles under the eyes. The company has also been running Facebook ads, which appears to be a roundabout way of getting people to their web site, given that most content on Facebook links there.

The Facebook pages of  Avon, Mary Kay and Cover Girl seemed like after-thoughts created primarily to drive traffic to their web sites; neither made effective use of Facebook by making a visit to their page unique for their fans. Rather, they just provided a lot of content that fans could find on their company web sites.

Mary Kay linked most content to its primary web site, including the sales representative locator function and the Virtual Makeover feature — in which users upload photos to try out different Mary Kay products on their avatar. However, that web site feature does not use Facebook Connect. This seems like a missed opportunity. Why not ask users coming from Facebook to use Connect to sync with the site, then upload their Facebook profile photos to play around with the feature?

Cover Girls’ page wasn’t much better, as most content linked back to their web site. Polls and videos were posted on the walls to promote interaction, but so were promotions to Proctor & Gamble sister companies Oil of Olay and Secret, which distracted from Cover Girl’s presence on its own Facebook page. One highlight was a Lashes Contest tab that utilized an app to allow Facebook users to enter to win a trip to New York by uploading a photo of themselves wearing Cover Girl’s products.

Overall it seems that most makeup companies use Facebook marketing to boost their web sites, with the notable exception of Mark, which uses Facebook to keep users on the site and gets their info to try to keep them as future customers; perhaps this is due to Mark’s stated goal of targeting younger women?

Going forward, we expect to see more serious experimentation from the other brands as they try to reach their target audiences on Facebook.