A study by a computer security lab has found that porn sites "harboured malware or used "shady" practices to squeeze money out of their visitors," according to an article by the BBC on the study.

(In other news, rocks are hard and water is wet.)

Researchers from the International Secure Systems Lab reportedly analyzed 269,000 websites hosted on 35,000 domains -- more than 90 percent of which were free -- to see which hosted malicious software. About 3.23 percent of these sites were booby-trapped with adware, spyware, and viruses, the study reported.

While this doesn't sound like much, it's a problem because about 40 percent of visitors to such sites have vulnerabilities in their systems, further research reported. The researchers created their own porn sites and paid to have traffic sent there, and analyzed the computers and browsers of their visitors. Analysis of the 49,000 visitors sent to their sample sites showed that 20,000 were using a computer and browser combination that was vulnerable to at least one known exploit, the BBC said. More than 5,700 visitors had multiple vulnerable components, reported the Huffington Post.

Finally, researchers found that porn sites often used "shady" practices to keep visitors onsite, including Javascript catchers that make it hard for people to leave a page, or scripts that re-direct visitors so when they click on a link they do not see the video or image they were expecting but are passed to an affiliate site.

Online MBA released statistics earlier this year about pornography and its users, including:

• 12 percent of websites on the net are pornographic -- 24,644,172 sites.
• Every second, $3,075.64 is being spent on online porn and 28,258 users are viewing online porn.
• A quarter of search engine queries (around 68 million a day) are related to porn.
• The top pornography-related search terms are "sex," "adult dating," and "porn." There are some 116,000 searches for "child pornography" daily.
• 35 percent of downloads are pornographic.
• 2.5 billion email messages per day -- 8 percent -- are pornographic.
• Sunday is the most popular day for viewing porn online. Thanksgiving day the least popular day.
• The average age at which a child first sees porn online is 11.
• Twenty percent of men and 13 percent of women say they have watched porn online while at work.
• 70 percent of men aged 18-24 visit porn sites in a typical month. 1 in 3 porn viewers are women.