Sometimes, it pays to be a follower.

Twitter and Facebook have been a marketing godsend for all kinds of companies, which increasingly are using the social media to build loyalty with shoppers. Now, retailers have begun to tout sales and exclusive discounts to customers who interact with them through these outlets. For example, Banana Republic recently offered shoppers an invitation to an exclusive spring preview event, as well as a printout coupon good for 30% off a purchase of $100 or more at the event.

Of course, the businesses are not simply trying to be nice with such offers. They are subtly trying to shape consumer perceptions. Developing a social media presence lets companies more effectively manage what customers are saying about their business online by developing a following, says Lyn Mettler, the founder of Step Ahead, a marketing firm in Mt. Pleasant, S.C. "They might as well get in on the conversation and offer something to reward the loyal customers," she says.

What's more, the scope of the offer can be limited, either in the selection or time frame. To find freebies, look for businesses located in your area as well as nearby locations of major chains. They have more need of brand recognition and customers than a big-name company, and so are more likely to offer exclusive discounts for followers, says Sara Dunham, a spokeswoman for Savings.com.

To find deals, register for the free networking sites and search for your favorite companies and brands. Some have coupon-specific feeds or pages that put deals all in one place.

Here are seven companies offering deals through social media:

Twitter

Dell's outlet division regularly posts exclusive online sales.They sell primarily refurbished and open-box items, so expect limited selection.

Recent tweet: (Feb. 19) "Save up to 40% on select tax preparation software! - Offer ends 2/23 at 7am CT"

Office Depot's sale and coupon feed.

Recent tweet: (Feb. 17) "Save up to 40% on your favorite supplies"

JetBlue's weekly feed of Twitter-exclusive deals has new offers every Tuesday.The last-minute fares tend to sell out quickly. Be prepared to act fast .

Recent tweet: (Feb. 16) "$29 BUF to JFK this Sat. JFK-BUF this Mon. or Tues. 25 seats avail or til 6pm ET. Taxes, Fees, Rest. apply"

California boutique hotel chain Joie de Vivre Hotels offers Twitter Tuesday and Facebook Friday deals.

Recent tweet: (Feb. 19) "Facebook Fridays is here! Our fabulous Hotel Los Gatos is running rates starting at $159 per night (good on...)"

United Airlines' offers exclusive "Twares" fares amid customer service and policy posts. The fares are fast-selling; if you want the deal, you d better pay attention to the feed.

Recent tweet (Feb. 19 -- new Twares post regularly) "Virginia is for lovers! Still haven t celebrated Valentine s Day? Travel to Virginia with our Tware! Details @ http://tinyurl.com/ya7rdpz"

Facebook

Check for coupons and sale notifications amid collection previews, contests and brand discussions.

Recent post: (Feb. 18) "You re invited to be the first to shop our new spring chino collection and save. As a special offer to Facebook fans, RSVP and you'll receive an exclusive 30% off your purchase of $100* or more during the party [on Feb. 23]. Print this page and take it to your nearest store to receive your discount."

Coupons, sales and deals. Check the coupon tab for more exclusive deals that may not show up in the regular sale feed.

Recent post: (Feb. 18) "Did you like Hot Wheels when you were a kid? Free Hot Wheels Supercar Vehicles With $25+ Hot Wheels purchase. Get free Hot Wheels Supercar vehicles with any Hot Wheels purchase of $25 or more at Toys"R"Us! Offer expires on 2/20."