Mario Tama/Getty Images

PHILADELPHIA, PA - MAY 24: Former Massachusetts Gov. and Republican candidate for president Mitt Romney (2nd L) greets students in a third grade computer technology class at Universal Bluford Charter School on May 24, 2012 in Philadelphia, Pennsylvania. Romney took part in a roundtable discussion and toured classrooms. Romney said federal funds under his new education plan will allow low income children to attend any school in their state. (Photo by Mario Tama/Getty Images)

Have you ever shopped online for a pair of shoes? Or maybe looked at flight from LA to New York? Even if you never made the purchase, ads for those things will start to pop up on every site you visit. It's form of advertising called"online targeting." It starts when a company identifies you as a potential customer based on your browsing history. Then that company buys up ads on the pages you visit.

While it's nothing new in the consumer world, it's now moving into the political realm. Both Barack Obama and Mitt Romney have hired a team to help find and advertise to potential voters on-line.

Guest:

Lois Beckettis a reporter and she has been looking into this phenomenon for Pro Publica.