A case study: The danger of 'freemium'

At the Freemium Summit in San Francisco, Mailchimp CEO Ben Chestnut discusses the abuse that ensued after his e-mail marketing service Mailchimp started using a "freemium" model for his business. While user base grew 240 percent in seven months, he also faced new obstacles such as "fuzzy spam." Chestnut talks about his business challenges with spam and what he's doing now to fight it.