Matthew J. Mimiaga is with the Fenway Institute, Boston, MA, and the Harvard Medical School/Massachusetts General Hospital, Boston. Andrew D. Fair, Ashley M. Tetu, and Rodney VanDerwarker are with the Fenway Institute, Boston. David S. Novak and Thomas Bertrand are with the State Laboratory Institute, Division of STD Prevention, Massachusetts Department of Public Health, Jamaica Plain. Stephan Adelson is with Online Buddies Inc, Cambridge, MA. Kenneth H. Mayer is with the Fenway Institute, Boston, and...