Although always important, this task is particularly critical in the case of Internet sources. Suppose the researcher finds two articles, one from a traditional information source, a medical encyclopedia, and one from the Internet. Understanding the differences between these kinds of sources helps to demonstrate why it is especially important to evaluate Internet sources. Compared to a medical encyclopedia article, an article found on the Internet is likely to be different in a couple of important ways. First, the type of article is likely to be very different.
Medical encyclopedias tend to contain factual, objective introductory information.
Web sites, on the other hand, are very often advocacy sites, taking a particular side of an issue and arguing for it. They may also be personal in nature, or commercial, selling a product. Of course, you may find a medical encyclopedia or other objective health site on the Internet, but other types of sites are more common. Second, and more importantly, the process for publication differs greatly between these two sources. In the case of the medical encyclopedia article, the researcher can make several assumptions.