Actually, I'm shocked that Google revealed the correct diagnosis in only 58% of cases. (Using Google Scholar instead might have increased the yield.) From the British Medical Journal (Free Full Text):
Objective To determine how often searching with Google (the
most popular search engine on the world wide web) leads
doctors to the correct diagnosis.
Design Internet based study using Google to search for
diagnoses; researchers were blind to the correct diagnoses.
Setting One year’s (2005) diagnostic cases published in the case
records of the New England Journal of Medicine.
Cases 26 cases from the New England Journal of Medicine;
management cases were excluded.
Main outcome measure Percentage of correct diagnoses from
Google searches (compared with the diagnoses as published in
the New England Journal of Medicine).
Results Google searches revealed the correct diagnosis in 15
(58%, 95% confidence interval 38% to 77%) cases.
Conclusion As internet access becomes more readily available
in outpatient clinics and hospital wards, the web is rapidly
becoming an important clinical tool for doctors. The use of web
based searching may help doctors to diagnose difficult cases.