Online databases can be searched by keyword. It is the world's largest such database. In May 1996 it contained about eight million references published since 1966 and was adding about 10,000 new ones per week. Several drug companies are advertising with Web pages, one of which offers a list of recommended physicians and a discount coupon. The Internet has no central index, but the World Wide Web offers special pages, called search engines, that index large portions of the Net.
Online sources provide peer communication, anonymity, convenience, and rapid responses.
The information is voluminous but not necessarily accurate. Virtually anyone can create an online resource and make it generally available. This includes not only health professionals but also ordinary people who believe they have been helped by a product, companies with a financial stake in the information they provide, and even outright charlatans. However, neither book indicates how to distinguish reliable from unreliable sources. The 1995 Health Informatics Directory describes more than 400 computer products for patient education, health promotion, and informed decision-making.