Powerset is "natural language search." What that means is that instead of searching the Web based on keywords, like Google does, it searches on meaning. Powerset understands what a search query means, and it understands what every sentence it has indexed is about, too. The company's shining example (which is getting a little old) is this: If you enter the query, "politicians who died from disease," Powerset will return a list that begins, "Edward Heath," with the supporting snippet from Wikipedia, "Sir Edward heath died from pneumonia." It says this because it knows that Heath was Prime Minister of England (and thus a politician), and that pneumonia is a disease.
Read more here.
