Your brain can store 4.7million books. Yes, really

Sometimes, as you hunch over a fiendish Sudoku or nurse the hangover-to-end-all-hangovers, it might occur to you that that mass of fat and neurons sitting in your skull is a useless bit of junk.
But don’t do yourself down. Your brain has the capacity to retain 4.7billion books, scientists have discovered, or ten times the number originally thought.
On average, one synapse can hold roughly 4.7 bits of information, which means that the human brain can hold one petabyte (1,000,000,000,000,000 bytes).

One petabyte equates to 13.3 years of HD TV recordings, 20million four-drawer filing cabinets filled with text, 670million web pages or 4.7billion books. Not bad.
Professor Terry Sejnowski and his team at the Salk Institute for Biological Studies, in California, stress that this is the total amount of information that the particular part of the brain could carry, in theory, at any one time, and its actual archive of memories would likely be a lot smaller. Regardless, the discovery is, he says, a ‘real bombshell in neuroscience.’
‘Our new measurements of the brain’s memory capacity increase conservative estimates by a factor of 10 to at least a petabyte, in the same ballpark as the World Wide Web,’ he said.