Full reviews were conducted on 37 public websites on health behavior change for disease prevention and management. All had at least four of five of the `5A's for effective health behavior change treatment on the Internet' (advise, assess, assist, anticipatory guidance and arrange follow-up) that are assumed to be minimum criteria for a program to have the potential for producing behavior change. The strength of these 37 programs included: rationales provided for assessments; privacy and confidentiality protections; some form of feedback provided; and some form of interactivity. The weaknesses included: few were theory driven; few had individualized tailoring; few had empirically based tailoring; and few were evidence based or reported subsequent plans for evaluation.