Along the same lines as Google Flu Trends, researchers at Microsoft, Stanford and Columbia University are investigating whether search data can be used to find interactions between drugs. They recently found an interaction.
Using automated software tools to examine queries by six million Internet users taken from Web search logs in 2010, the researchers looked for searches relating to an antidepressant, paroxetine, and a cholesterol lowering drug, pravastatin. They were able to find evidence that the combination of the two drugs caused high blood sugar.
The idea is that people are searching for symptoms and medications, and this data is stored in anonymized search logs. They then followed a suspicion that using the two drugs at the same time might cause hyperglycemia. Those that searched for the two drugs were more likely to search for hyperglycemia than the control group (probably those who didn't search for hyperglycemia).
The work is still in its infancy, but it'll be interesting to see how this sort of data can be used to supplement existing work by the Food and Drug Administration.