单选题 Yesterday, at a panel I moderated (充当调解人) in San Francisco, Donna Wells, Mint. con's chief marketing officer, stunned a room full of digital marketing pros by noting that she really didn't have much of a marketing budget. Mint. com has gone from zero to 1.5 million users in two years with no ad campaign, save a mid—five—figures sum spent on search engine terms. Rather than purchase traffic, it has pursued the same type of strategy that food trucks and online magazines do : Using free social media and piggybacking (附带) on popular new communications technology. Mint. com has more than 36,000 Facebook fans and 19,000 Twitter followers, a well - trafficked blog, and a popular iPhone application.
How has Mint. con successfully promoted its fame in the last two years.'?

• A. With ad campaigns.
• B. By purchasing traffic.
• C. By using free social media.
• D. Through cooperation with other websites.