Can you hear me now? Unsuspecting cellphone users may find themselves saying that more often now that cellphone jammers — illegal gizmos that interfere with signals and cut off reception — are selling like hotcakes on the streets of New York. "I bought one online, and I love it," said one jammer owner fed up with the din of dumb conversations and rock-and-roll ringtones. "I use it on the bus all the time. I always zap the idiots who discuss what they want from the Chinese restaurant so that everyone can hear them. Why is that necessary?" He added, "I...