According to a recent study by security firm Symantec, you are far more likely to encounter malware when visiting religious web sites than when visiting, ahem, adult sites. In an article describing the finding, Network World had this to say:
Symantec found that the average number of security threats on religious sites was around 115, while adult sites only carried around 25 threats per site–a particularly notable discrepancy considering that there are vastly more pornographic sites than religious ones. Also, only 2.4 percent of adult sites were found to be infected with malware, compared to 20 percent of blogs.
In (related?) news, the University of British Columbia reported a study showing that encouraging people to use their analytic thinking skills causes a reduction in religious belief, even in pious persons. Unfortunately, the study did not touch on whether the reduction in superstition was tied to increased use of, ahem, adult sites.