use of clickstream data can raise privacy concerns, especially since some internet service providers have resorted to selling users' clickstream data as a way to enhance revenue. there are 10-12 companies that purchase this data, typically for about $0.40/month per user. while this practice may not directly identify individual users, it is often possible to indirectly identify specific users, an example being the aol search data scandal. most consumers are unaware of this practice, and its potential for compromising their privacy. in addition, few isps publicly admit to this practice.