Segmentation - Just Say What You See.
The blinkering effect of targetting your product/service towards a specific demographic was reinforced to me by a series of disparate conversations I had in the last couple of days. Firstly, Lee Thomas was telling me about the committee-style marketing of an urban movie which decided on an 18-25 year old male focus, but then wanted to sex up the poster so as to appeal to women.
Later that day, I was chatting to Hugh Macleod and was reminded that part of the success of English Cut came from simply answering the question "Who would buy an expensive suit?"
You might respond people with a style obsession, people desiring to show off or people whose parents bought expensive suits. All may or may not be valid answers, but the commonality is simpler. The people who buy an expensive suit are people who can afford to buy an expensive suit. That single, profound realisation opened up a whole new market for the business amongst successful geeks.
Then online, I was trying to add to a blog conversation by supplying the answer to a question that had been raised, specifically the identity of an american choir of retirees that had featured on a TV documentary.
Googling "oldest choir" only led me to longest established choirs. Even adding in "documentary" and "British TV" to my search term didn't help. Like any other adjective/attribute, oldest means different things to different people. So I focussed on what they really were. I searched for the real commonality and googled "old people singing". Et voila. Success.
Segmentation is about the group of people who want the attributes you are offering. They decide, not you. So it's much better to focus on what those attributes are rather than the specific collective identity of those who value them. Urban movies will be watched by people who like the genre, expensive suits will be bought by people who can afford them and your product/service will be bought by people who value it. That's who and how you should be targetting. Demographic subdivisions are not.