Here is a great call for Open Linked Data by Ian Davis from Talis:
Conjecture 1: Data outlasts code , therefore open data is more important than open source.
Conjecture 2: There is more structured data in the world than unstructured, therefore people who understand structure matter.
Conjecture 3: Most of the value in our data is unexpected and unintended, therefore we should engineer for serendipity
I am not sure about Conjecture 2. I thought there was more semi-structured and unstrctured data than structured data, but I could be wrong about that.
So what does it take to discover the unexpected and uninteded value of data? Data Mining with machine learning algorithms?