The theory of Jobs To Be Done explains that too much focus on socio-demographic data and correlations hurts companies. Rather, you have to gain a deeper understanding of your customers, who "hire" your product to help them do certain jobs under certain circumstances. For instance, you don't buy a video game console because you're male and over 30. You hire it to, e.g., do the job "connect with friends".
2008 – Tales of Design & User Experience 