In our recent Guerrilla Marketing report (ER-04-6), we focused on low-cost marketing tactics. In this follow-up report, we consider technologies that can be used to increase marketing effectiveness, enhance customer take rates, cut marketing costs, and improve returns on investment. We review innovative uses of e-mail newsletters, blogs, viral marketing, ecommerce, customer forums, web conferencing, interactive voice response (IVR) systems, optical scanning, and other technologies. (ER-04-16; November 2004; 23 pages)