Fourth, you need to be able to tell quickly who owns the site and where the money comes from to keep it going. And fifth, the timing of material that's put there and if it's been updated should be clearly stated. I think for consumers it's best to go with name brand identification. If you can trust The National Institutes of Health and the National Cancer Institute in general, you can trust their web site. Other than that, it's the same.
Information is information no matter where.
Process is process no matter where. Ethics are ethics no matter where. Trustworthy people are trustworthy people no matter what medium they're in. Most of what is on the Internet is the same as it would be in person or in print form, it's just that the Internet is a different medium. There should be healthy skepticism.