1. Amazon.com, Recommendation Center, http://www.amazon.com
2. Aptex Software Inc., SelectCast Affinity Server, http://www.aptex.com/products-selectcast-ads.htm
3. Associated Press, Personal habits gathered for use on the Internet, CNN interactive, Atlanta, GA, August 16, 1998, available at http://www.cnn.com/TECH/computing/9808/16/website.privacy/
4. P. Baudisch and D. Leopold, User-configurable advertising profile applied to Web page banners, in: Proc. 1st Berlin Economics Workshop, Berlin, Germany, October 1997, see also the Postscript file called `baudisch1997bUserConfigurableAdvertisingProfiles.ps' at http://www.darmstadt.gmd.de/∼baudisch/Publications/
5. R. Briggs and N. Hollis, Advertising on the Web: Is there response before click-through? Journal of Advertising Research March/April (1997) 33–45.