Back when mastodons still walked the earth, cell phones made phone calls, period. So cave men could call home to say the hunt had been successful, but certainly couldn’t send a picture to illustrate their prowess. Now, of course, cell phones are high-powered multimedia packages that can access the whole world and everybody in it, posting tweets to Twitter, passing thoughts to Facebook friends and sending text messages to everyone. The Internet, photos, games, GPS, email, TV and videos are all flowing into these handheld powerhouses. You probably take for granted that these different functions all work together despite...