Both types of data can transform the world, but when government turns big data into open data it's especially powerful.
Big data and the new phenomenon open data are closely related but they're not the same. Open data brings a perspective that can make big data more useful, more democratic, and less threatening.
While big data is defined by size, open data is defined by its use. Big data is the term used to describe very large, complex, rapidly-changing datasets. But those judgments are subjective and dependent on technology: today's big data may not seem so big in a few years when data analysis and computing technology improve.
Via Elizabeth E Charles