VentureBeat is reporting that Microsoft has agreed to acquire Powerset Inc., a San Francisco-based developer of a natural language search engine. The deal is expected to be formally announced next month, with a sale price in the ballpark of $100 million.
Powerset raised $12.5 million in Series A funding in late 2006, at a post-money valuation of $42.5 million. It has since raised another $4 million in convertible note financing. Backers included Foundation Capital, The Founders Fund and individual angels like Esther Dyson.