Inbound marketing software company HubSpot had a great 2012, growing customers by 42 percent and revenue by 82 percent to $52.5 million. That type of growth is difficult to achieve at this scale, but the company’s 8,440 small business customers were likely happy to pay given that they increased their traffic 92 percent of the time, and grew inbound leads 93 percent of the time. The company raised $35 million in mezzanine financing last year, bringing its total financing to $101 million. [Source: HubSpot]