Sarah was born in 1989, the same year as Hayden Panettiere (the cheerleader from Heroes) and Daniel Radcliffe (who plays Harry Potter). Sarah was six when Toy Story came out and nine years old when the first Harry Potter book was published. Sarah has always had a cell phone. She's always had access to the internet.

And Sarah is entering college this week.

Imagine being a college professor today. One who went to college in the 60s or 70s is teaching students who think of Vietnam as a prime vacation spot, not a war. Could you connect with Sarah?

For a decade, Beloit College has produced the Mindset List, describing the reality of an 18-year-old for their much older professors:

The "Class of 2011" refers to students entering college this year. They are generally 18 which suggests they were born in 1989. The list identifies the experiences and event horizons of students as they commence higher education.

So, for the incoming freshmen, the Soviet Union has never existed and therefore is about as scary as the student union.

Creating a persona is not a creative writing exercise although it certainly helps to be creative. Instead, persona development is grounded in research. We at Pragmatic Marketing know product managers: we visit dozens of them weekly; we survey hundreds in our annual survey; I can review their technical stats in my website logs.

When was your persona born? What were the popular names that year? Create a persona based on market research and then use NameVoyager for picking statistically relevant names. It shows the popularity of names in the U.S. for the last 100 years.

Do you know your customers? Are they fictional characters? Or are they archetypes grounded in research? Personas give us a programming and marketing target. Let's make sure that everyone in the company has clarity on our customer.