If you've not heard of the recent discovery of some rather concerning data-wipe vulnerabilities with the Samsung Galaxy S III specifically, it's time to read up - your phone could be hit as well. Developer / researcher Ravi Borgaonkar has found several devices of all kinds to be venerable to the less-than-pleasing way in which hackers may be able to jump right into your device and knock it out entirely. What you're going to want to do as soon as possible is pick your device up and update your software as fast as you can.
The reason you're going to want to be concerned about this situation is not that there are hackers out there right this minute actively attempting to exploit you, but that the software break that's been found here would make it a lot easier if someone wanted to try. What the warning here includes is a note on how something so simple as a link on the web, clicked through your smartphone, could trigger an attachment that's capable of destroying your device's memory.
This break has actively gone through on early production versions of the Samsung Galaxy S III and more devices are at risk - in theory - from Motorola, HTC, Sony, and Samsung. That's pretty much the whole spread of popular manufacturers with their own custom software additions to Android. Incidentally, it appears that the Samsung Galaxy Nexus was never venerable because of its Google-only software build.
What you're going to want to do to stay out of the way of danger is to check your software to see if you've got an update waiting for you. Most often this exists inside your settings, all the way down at the bottom under Phone Info (or something similar), and Software Update. Each smartphone manufacturer has a slightly different place for this update, but they're pretty nearby one another, so make it happen!