Well, what do you know, it looks like Apple’s ambitious messaging service unveiled Monday as part of the iOS 5 software is seen as a threat to Research In Motion’s popular BlackBerry Messenger instant messaging protocol for BlackBerry devices. According to TechRadar, investors punished the BlackBerry maker’s stock Tuesday as they digested Apple’s iMessage:

Why are investors worried about iMessage affecting RIM’s chat service?

Well, as author Kate Solomon pointed out, “until Monday, BlackBerry Messenger was the only IM service of its kind and had proven very popular with the teenage market”. With that in mind, iMessages and BlackBerry Messenger are obviously after the same market segment. Given RIM’s insistence that it has seen significant growth in the teenage market over the past couple of quarters, it doesn’t take a rocket scientist to figure out that Apple’s iMessage service could easily erase RIM’s advantage with some youngsters who fell in love with their BlackBerry’s because they can IM like crazy without using up costly SMS messages.