When it comes to niche markets they don?t get much bigger than the Baby Boomers, the upper range of which is targeted by Jitterbug, an MVNO aimed at seniors who are uncomfortable with mobile technology which launched last October. BusinessWeek has a good overview of the service and its range of content?or more specifically its intentional absence of a range of content. The menu system on the Samsung-manufactured handset has been replaced by a series of questions with a yes or no response and as much of the service as possible has been removed from the handset and put on the web. My personal favorite is replacing the signal strength reader with a dial tone?no dial tone, no service. The handset is strongly integrated with the service, for example the voicemail system fit with the yes/no options on the phone. There?s unlikely to be much interesting mobile content for the service, but it is a good example of thinking about the needs and wants of a niche and answering those needs and wants, rather than just sticking a brand name on an over-priced phone.