The Corporation for Public Broadcasting is awarding $4.1 million to help American Public Media expand its digital Public Insight Network, it announced today (Sept. 15). PIN gathers more than 120,000 citizen sources who share their knowledge with reporters in 45 newsrooms, including 15 of the top 20 media markets (background, Current, Jan. 24, 2011). CPB said its investment will add more than 100,000 new sources and bring PIN to 50 additional newsrooms.