Rob writes to tell us that at the recent Open Source Business Conference in San Francisco Microsoft's director of platform technology strategy, Bill Hilf, outlined why Microsoft is staying involved with open source. From the article: "Challenges of working [coopetively] in the open-source space include the balance between competing and cooperating with a rival, he said. Perception also is a 'big' challenge for the software giant. 'In many regards, the Microsoft open-source story lends itself to a great metaphor of David and Goliath,' he said. 'That is a challenge over perception.'"