News From NPR

Crowdsourced review sites like Yelp can be just the trick for finding a great restaurant or avoiding a bad one.

But when it comes to finding a good doctor, there still aren't enough reviews on sites that rank doctors to make them reliable, a study of urologists' ratings suggests.

Urologists averaged just 2.4 reviews on the big online doctor rating sites like Healthgrades.com, Vitals.com and RateMDs.com. The paltry number of participants means that one cranky patient's complaint — or a rave from one doctor's relative --can skew a rating.

The first key to thinking about 3-D printers is this: Do not think printer. Think magic box that creates any object you can imagine.

In the box, razor-thin layers of powdered material (acrylic, nylon, silver, whatever) pile one on top of the other, and then, voila — you've got a shoe, or a cup, or a ring, or an iPhone case.

It's miraculous to see. Press a button, make anything you want. But just how important is 3-D printing? Unlike earlier big-deal technologies (like, say, the tractor) 3-D printing won't really replace what came before.