6. Earn money for referring friends

What credit card issuers hope their social media presence brings them, more than anything, is word-of-mouth advertising. To encourage it, some offer incentives to customers who refer others online. Discover, for instance, has a program called Refer a Friend, which gives cardholders $50 in cash back for every friend referred via email, Facebook, Twitter or LinkedIn who eventually gets a Discover card. According to Discover, its cardholders have earned almost $2 million in cashback bonuses since the program's inception. American Express and Citi have run similar programs in the past.

7. Get smart

Finding the right mix of content -- "some entertainment, but also some meat" -- drives customer satisfaction with social media, according to Anderson. Credit card companies strive for that mix on their YouTube channels, where American Express, Capital One and Citibank post fun commercials alongside informative videos about card features. On Capital One's YouTube channel, for instance, you can see a demo of the card company's Purchase Eraser -- a way to redeem miles for travel you've already purchased. Wells Fargo's YouTube channel videos are crammed with basic info on establishing and protecting credit.

8. Buy things

A ground-breaking new addition to credit card companies' social media outreach: the ability to instantly charge things with social media. As part of American Express's Sync program, registered cardholders can actually make a purchase without leaving Twitter. Just respond to an offer with a special hashtag -- for instance, #buyKindleFireHD -- then confirm your purchase, and boom, it's on its way.

9. Get news

You likely don't care about the ho-hum company press releases that credit card issuers disseminate through social media, but other news flashes hit home. Wells Fargo, for instance, hopped on Facebook to let customers know about a denial-of-service cyberattack that rendered its website inaccessible. "Rest assured that your account and personal information are safe," it added, encouraging frustrated customers to call for service. When Hurricane Sandy hit the East Coast, Citibank tweeted that customers could get in touch for help, and Wells Fargo took to Twitter to remind customers to get cash before Sandy struck.

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10. Complain -- and get results

In an epic example of using social media to change credit cards for good, 22-year-old Molly Katchpole went online in 2011 to fight against Bank of America's proposed $5-a-month debit card fee. Her petition at Change.org went viral, sparking a massive consumer backlash. The bank was inundated with complaints on Twitter and Facebook, and ultimately decided to abandon its plans. So did several other card issuers, including Wells Fargo, Citi and JPMorgan Chase, which had been considering similar debit fees. Ah, the power of social media.

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