I think that both approaches can have positive benefits. When marketing to a specific segment, marketers can get more information on the particular target market. Since they know exactly who they are marketing to, they will be able to do more research and be able to learn more about this specific target market. A downside to this, however, is that when only marketing to a specific target market, a company may miss out on appealing to many more people. Since most of the marketing efforts will be going into a specific target market, those outside this target market may not be marketed to and the company may miss out on sales.
When mass marketing, however, a company can attempt to appeal to everybody all at once. This can be very beneficial since everyone will be exposed to the marketing and such a large audience is being reached. The downside to this approach will be the lack of information, preferences, and overall research about the customers in the market. Since it is very difficult to do research on an entire market, many marketers may have a tough time deciding what kinds of advertising, products, etc. to supply to a market, which can be easier when marketing to a target market. Since preferences in mass marketing can differ greatly, it may be difficult for some companies to market their product as successfully as if they were trying to appeal to a target market.
Overall, I think that each approach can have many positive and negative aspects, and a company should tailor its needs to what it thinks will be better. Do you agree that there may be no clear cut winner?