Table 2.

List of all used sources with the available attributes.

Dataset	Age	Gender	Ethnicity	Location	Writing level
TwitterHealth	No	Gender classifiera	Ethnicity classifierb	Yes	Writing level classifier
Google+Health	Yes	Yes		Yes	Writing level classifier
Drugs.com	No	Gender classifierc	No	No	Writing level classifier
DailyStrength/Treatments	Yes	Yes	No	Yes	Writing level classifier
WebMD/Drugs	Yes	Yes	No	No	Writing level classifier
Drugs.com/Answers	No	Gender classifierc	No	No	Writing level classifier
DailyStrength/Forums	Yes	Yes	No	Yes	Writing level classifier
WebMD	No	Gender classifierc	No	No	Writing level classifier

^aFirst name.

^bLast name.

^cScreen name.