Commercial sites may represent a specific company or be sponsored by a company using the web for commercial reasons—to sell products.
At the same time, many commercial websites have valuable and credible information. Many hospitals have .com in their address.
The site should fully disclose the sponsor of the site, including the identities of commercial and noncommercial organizations that have contributed funding, services, or material to the site.
Source: The Medical Library Association's A User's Guide to Finding and Evaluating Health Information on the Web
1. Sponsorship
2. Currency
3. Factual information
4. Audience
Source: The Medical Library Association's A User's Guide to Finding and Evaluating Health Information on the Web