The value of "big data" lies less in its volume than in its variety. This is the gist of a recent report from the McKinsey Global Institute, Big data: The next frontier for innovation, competition, and productivity. […] On the vendors' side of the house, Stephen Brobst, Teradata's chief technology officer, has told us: "It's not actually the size of the data that matters as much as the diversity. One important factor is the transition from transactions to interactions. This creates big data."
via NoSQL databases