Adtech company Marin Software has filed its S-1. The company, launched in 2006, has more than 500 advertising customers, having deployed $3.2 billion in ad dollars in 2011. However, it has not yet turned a profit, losing $17.4 million in 2011 and $19.2 million in the top three quarters of last year. Said the company in its S-1: “We do not expect to be profitable in the foreseeable future and we cannot be certain that we will be able to attain profitability on a quarterly or annual basis, or if we do, that we will sustain profitability.” [Source: Adweek]