With companies like knewton and amplify garnering success, and acquiring big clients, is there a market for small startups to enter into this newish (midterm horizon) field?
You'd be surprised. Education, typically a very not-for-profit industry, is exploding in new ventures. And yes, utilizing open data is working for several startups. Check out GreatSchools.com (no affiliation) to see what they're doing with edu and data. If you're interested in this niche, ask questions like "What information (data) would parents want in choosing schools, colleges, scholarships, etc." Find an answer that needs answering....there ya go!