Big Data, and its cousin the Smart Cities movement, are both increasingly dismissed as fads and technology marketing schemes—and worse for some, examples of a too-reductionist science gone amok. The charges are worth considering.

But the vast streams of data are already with us. (For example, humanity has now generated and stored almost 8 sextillion bytes of data—many times the number of grains of sand on all the beaches of the world.)  The more pointed question is, therefore, how we will manage this already existing technology and what it might offer us as a resource, beyond the hype, to deal with our most pressing human challenges.

Unquestionably there are dangers in Big Data, in threats to privacy and in disorganized, overwhelming data—too much "noise" and not enough "signal."  Alarmingly, there is also a runaway proliferation of trivial data and near-meaningless junk.

Star Trek actor George Takei recently held a contest on Facebook, asking entrants to describe the hardest thing to explain about life today to a time traveler from the 1950s. The winner: "I possess a device in my pocket that is capable of accessing the entirety of information known to man. I use it to look at pictures of cats and get in arguments with strangers."

The anecdote is funny, but it belies a serious threat to our species intelligence—to our ability to identify and solve our larger collective problems. Yet we have made some notable progress in curating useful knowledge among all the vast junkish information, on the Web and elsewhere.  Wikipedia, for example, is a very intriguing example of useful knowledge acquired through big-data, open-source collaboration, offering an instructive contrast with the increasing trend toward junky data. The challenge is to build on this and other successes with a new generation of data tools that help us to identify and collaborate effectively, notably on urban challenges.