The Post 200 is an annual snapshot of the companies, law firms, nonprofits and other organizations that power our local economy. Here’s a look at this year’s list. Public companies 59. Liquidity Services The company works with retailers, government agencies and others to sell surplus goods online. Since its inception, it has helped sell off more than $3 billion in excess goods. In July, the company acquired GoIndustry DoveBid, a global provider of management, auction and valuation services. The purchase expanded the company’s footprint to 25 countries and added 50 Fortune 1000 clients. Trivia In 2012, the cumulative sale of scrap metal through the company’s marketplaces reached 2 billion pounds.