Though consumers turn to Facebook primarily to connect with friends and fill downtime, product discounts and "social badging" are the most commonly cited motivations for "liking" brands on Facebook, according to a survey from ExactTarget and Co-Tweet.

Over two in five surveyed Facebook users (43%) say they "like," or are fans of, at least one brand on Facebook. Among them, 40% say they like brands to receive discounts and promotions, whereas 39% say they do so to publicly display their brand affiliations to others. By contrast, 23% of consumers who follow brands on Twitter do so for social-badging purposes.

Roughly one-third of Facebook users say they like brands in order to stay informed about company activities (34%) and get updates on future products (33%).

However, "liking" doesn't always lead to buying. Among Facebook users who like at least one brand, only 17% say they're more likely to buy after liking that brand on Facebook.

In addition, less than one-half of Facebook users say marketers are "welcome participants on social networks." But even those who welcome marketers say it's because they support free enterprise, not because they seek out interactions with marketers on Facebook.

Below, other findings from ExactTarget's study Facebook X-Factors, which examines how consumers are using Facebook.

Making Personal Connections

The most common reasons consumers use Facebook is to connect friends (63%) and maintain personal contacts (59%), whereas only 15% use the site to maintain professional contacts.

Nearly one-third (37%) of Facebook users visit the site to manage their social lives—and 30% use Facebook to fill their downtime, citing it as a "guilty pleasure."

As a source of personal connections and guilty pleasures, it's not surprising that 65% of Facebook users say they use the site only before or after work/school, and 69% do so on weekends or on off-days.

Women are more likely than men to use Facebook for maintaining personal relationships (63% vs. 54%), connecting with old friends (68% vs. 56%), and managing their social lives (41% vs. 34%).

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Consumers' Facebook Favorites

Asked what brands are doing the best job engaging consumers on Facebook, surveyed Facebook users cited the following brands as their top five:

• Oreo (Nabisco): Oreo, and parent company Nabisco, were frequently named as favorites among Deal Seekers across all age groups (consumers motivated to interact with brands online for coupons and freebies).

• Wal-Mart: Wal-Mart's 1.5-million fan base is small relative to many top brands, but their no-nonsense approach to highlighting cost-savings opportunities is appreciated by their customers—regardless of age and gender.

• Victoria's Secret: Nearly 6 million fans make Victoria's Secret the most "liked" fashion page on Facebook. Women, especially Millennials, frequently compliment the company's new product offerings featured on their Facebook page.

• iTunes: Also a favorite among Millennials, iTunes focuses on highlighting new movie and music releases on its Facebook page, and consumers appreciate the tight integration between Facebook and iTunes' music service.

• Dove: Though Dove has not reached even 200,000 fans, women appreciate the courageous stand the brand has taken in its "Campaign for Real Beauty." Many Facebook users cited the brand as a "shining star" on both Facebook and social media in general.

About the data: Findings are based on an ExactTarget survey of 1,506 consumers age 15+, conducted April 9-13, 2010, and consumer interviews among 44 people in March 2010.