Big Data is big business for colleges and universities.

Seeking to boost donations, many colleges and universities are buying data about alumni -- tracking everything from what type of car you drive to where you work.

The goal: to pinpoint how likely you are to give back, and how much. The more likely you are to give a big gift, the more mailings you will receive.

Schools are also using massive databases to try to get students enrolled in the first place.

Lists of millions of high school students, sold by The College Board and other groups, provide everything from their test scores and intended major to the sports they play, their ethnicity and whether their parents went to college.

University officials say the data helps them target students who are the best fit. But data privacy advocates like Dixon worry that the information could be used to discriminate.

"That's information that students should choose to give to schools, not what schools should be able to buy without the students knowing it," she said.

Related: New ways colleges target rich alumni