September 29 is national coffee day – one reason for Americans to appreciate Dunkin Donuts. Marketers may find another reason to appreciate the coffee franchise today: it offers them a model interactive social media campaign. The company has launched a contest that both engages its Facebook followers and turns them into brand advocates.

Dunkin Donuts' has a "Video Contest" tab on its Facebook page that details its Ultimate DD Coffee Fan Contest. Fans can enter to win a grand prize trip to Costa Rica and 60 months of free coffee, and first prize runner-ups have the chance to receive one year of free Dunkin Donuts' coffee. For its part, the company wins consumer-generated content that promotes its brand.

To enter the contest, Facebook fans must submit short videos filmed in DD restaurants in which they express their love of Dunkin's coffee. Then, fellow Facebook fans and friends of the contestants can vote on the best videos. Notably, videos will primarily be judged according to the level of "passion for the DD brand" they convey.

The contest is a fun engagement tactic that reinforces brand loyalty among DD's Facebook fans. To start, it requires consumers to reflect on why they love Dunkin Donuts. Then, it provides DD with consumer-generated content to share with other Facebook users, turning entries into word-of-web referrals. Long after a winner is selected, the videos will continue to serve as promotional content for the brand's page. Plus, the winners are rewarded with branded merchandise – even the trip to Costa Rica involves a stop at Dunkin Donuts' Coffee Lab.

Other companies may want to take Dunkin Donuts' lead and develop Facebook contests that are brand-focused and offer consumers prizes. Not only do these events engage existing fans, but they may help businesses find new ones. According to a report from Chadwick Martin Bailey and iModerate Research Technologies relayed by eMarketer, receiving promotions and finding fun and entertainment are two of the leading reasons that consumers become fans of brands on Facebook.