At O'Reilly Radar, James Turner interviews Brian Aker on post-Oracle MySQL:

"Few companies have Google-sized datasets though. The average sites you see, they're 10-20 gigs of data. Moving to a MapReduce solution for 20 gigs of data, or even for a terabyte or two of data, makes no sense. Using MapReduce with NoSQL solutions for small sites? This happens because people don't understand how to pick the right tools."