Wired has an article about how browser hijacking technologies which place adware, images, etc., on your computer may be resulting in people being falsely accused of accessing porn. I'm going to agree with Jack Bertram (page 2), and say that it does sound a lot like

"I have to say it's like insisting the dog ate your homework," said Jeff Bertram, a systems administrator in New York City. "Are you going to admit that you downloaded porn to your pissed-off spouse or employer? Or to a judge? Hell no, your honor, it wasn't me. The browser did it."

A convenient excuse, no doubt. But not unlikely. Those users still browsing with IE probably get popup porn ad images that end up residing in their browser cache (another reason for switching to Mozilla with the built in popup ad blocker). And I've seen users with computers crawling with adware, wondering why their system runs so slowly. Regardless, I'm sure they'll come a day when my son gets old enough to say, "Some software must have put that on my computer, not me." LOL