While negative advertising has been around in retail as well, usually it is based on the smaller share attacking the industry leader, not a back and forth battle. The classic examples are Pepsi vs. Coke and more recently Mac vs Windows:

 Usually the leader would ignore the competitor to maintain their brand’s positive image. However, a new trend emerging is an actual response from the leaders in the example of the recent Verizon and AT&T 3G ad campaign.  Verizon’s television ads display a map comparing the two coverages and even uses a play on words for AT&T’s exclusive contract with the popular IPhone, mimicking “There’s an app for that” with “There’s a map for that”.  The difference from other retail negative campaigns is that AT&T responded to these claims with an ad of their own showing their coverage map and even hired a Hollywood actor to deliver the message. Here are the two ads:

AT&T might have been just trying to dispel misleading accusations, but the fact that they rolled out a large-scale campaign instead of a simple press release is significant. The two companies even sued and countersued each other reminiscent of a bitter political campaign debate.  Whether this is a bigger trend or an isolated instance is yet to be seen.