The Atlantic piece is light on details, but the Sunlight Foundation has a blog post describing the technology used for text pattern matching, titled "Churnalism US: the Nuts and Bolts" (http://sunlightfoundation.com/blog/2013/04/23/churnalism-tec...). They've released the core matching code, called SuperFastMatch, as free software (https://github.com/mediastandardstrust/superfastmatch).