TL;DR: Fill a need.

Notice that knowing how to improve the product did not come from understanding the "typical" customer. It came from understanding the job. Need more evidence?

Pierre Omidyar did not design eBay for the "auction psychographic." He founded it to help people sell personal items. Google was designed for the job of finding information, not for a "search demographic." The unit of analysis in the work that led to Procter & Gamble's stunningly successful Swiffer was the job of cleaning floors, not a demographic or psychographic study of people who mop.

Why do so many marketers try to understand the consumer rather than the job? One reason may be purely historical: In some of the markets in which the tools of modern market research were formulated and tested, such as feminine hygiene or baby care, the job was so closely aligned with the customer demographic that if you understood the customer, you would also understand the job. This coincidence is rare, however. All too frequently, marketers' focus on the customer causes them to target phantom needs.