I read an interesting report (I think it was from McKinsey) about different tech clusters around the world, and which had succeeded or failed. One major theme (as the report was mainly aimed at policy makers) was government support; was it helpful or harmful?

One finding was that when it came to financial support for startups, government acting alone (ie allowing some random beauracrats to decide which startups to give grants to) was counter-productive. But working with VC firms (ie governments investing in VC firms or some kind of matched investment scheme) generally saw good results. (Passion Capital in the UK and various initiatives in Israel were both given as examples IIRC).