N2H2 Inc., a Seattle-based company that provides schools with internet filtering software, has been collecting data on students’ web-surfing habits and sharing it with marketing firms for five-figure fees. The company’s software, known as “Bess,” is used by schools serving about 14 million children in North America.

N2H2 says it has tracked this information in order to improve its software and learn about students’ web-use patterns. However, the company has been selling that aggregated data through Roper Starch Worldwide Inc., a New York City-based market research company. It is charging firms $10,000 to $20,000 per year for the information. While the sharing of data seems to contradict N2H2’s promises of confidentiality, the company does not identify individual students or even individual schools.

Privacy advocates are especially concerned about the data collection, because most schools likely will be using filtering software in the near future to comply with a new federal law. They suggest that you discuss a vendor’s privacy provisions before signing up for its filtering software.