The screen capture above shows the results Google returned for my search on internet self-diagnosis. I was intrigued by the dramatic split between the content on the lefthand side of the page -- the actual search results -- and the sponsored links on the right.

As you can see, the top three results on the left all seem to discourage the practice of using the internet to find a diagnosis. Just to the right, on the same page, a series of advertisements urge Google searchers to do just that.

To be fair, not all of the ads mention self-diagnosis. Some appear to offer diagnostic services from medical professionals. But, as most doctors will tell you, the in-person examination is a key component of the diagnostic procedure.

Searching for medical information on the internet for the purpose of self-diagnosis is apparently common enough to merit its own diagnostic label: "cyberchondria." Here is Wikipedia's definition of the term:

Cyberchondria (or cyberchondriasis) describes the behavior of hypochondriacs who use the Internet to gather information on health or healthcare.

The particular danger of the internet for hypochondriacs is that serious and fatal conditions are overrepresented in search results for common symptoms. For example, a Google search for "headache" might show an article about brain tumors in the top five search results, in spite of the fact that the vast majority of headaches are not caused by brain cancer.