Market segmentation is a situation where humans try to fit other humans into broad categories. I think it must be almost fundamentally human to want to categorize for efficiency; it seems to be the most logical thing to do to approach a problem of mass appeal.
I think this is a decent idea, especially in the past where there wasn’t much available about each of your customers, but today, I think we need a more realistic way of telling us how each person buys. Rather than market segments, I think we actually exist in social segments; groups, cliques, socio-economic, levels. People who pursue the same interests and go to the same places generally have the same interests, and too a far degree, are probably more likely to buy the same kind of thing.
The market segmentation strategy as it stands seems to be hinged to one variable, increasing the number of variables until a comprehensive “portfolio” of consumer interests can be created. I think this iprocess yields results, but it is not quite as much “fitting” to the customer, as trying to see his purchase habits, and become the next one. I think the next logical step for this system is for a product to cater to a subculture of humans, as opposed to trying and guessing their next purchase from just their old recipts.