“Data is open if it can be freely accessed, used, modified and shared by anyone for any purpose – subject only, at most, to requirements to provide attribution and/or share-alike. Specifically, open data (…) requires that the data be A. Legally open: that is, available under an open (data) license that permits anyone freely to access, reuse and redistribute B. Technically open: that is, that the data be available for no more than the cost of reproduction and in machine-readable and bulk form” by the Open data Handbook (permalink).