A simple pop-up box has given the University of Pennsylvania a window into the minds of its online donors.

After donors make a gift to the university’s annual fund, a screen comes up that gives them a receipt for the donation, along with a pop-up box that asks if they would like to say why they made their contributions.

More than 650 donors have offered their comments since the Penn Fund added the box to its Web site in 2003.

Fund raisers are able to link the donors’ comments to their giving histories and look for patterns to help shape fund-raising strategy, says Jean Findlay, director of marketing and donor participation at the annual fund. They can, for example, look at the comments of donors who gave for the first time.

“That’s really important to me,” she says. “I need to figure out how to prompt more not-yet-givers into giving.”

Fund raisers have followed up on some of the stories and featured them in brochures and other fund-raising materials. Each person who fills out the form receives a personalized e-mail message thanking them for their comments within 24 hours.

Ms. Findlay says that it doesn’t take long for comments to start coming in after her office sends an e-mail appeal.

“It really feels good as a fund raiser to get the immediate gratification of seeing that people got the e-mail, they made the gift, and they’re telling us why,” she says. “With direct mail – forget it — you have to go on vacation and come back and look at the mail.”