What type of internet site is least acceptable as a source of accurate unbiased scientific information?

The simple answer would be .com because it indicates a private business. However, there can be no general determination of reliability based on the URL domain suffix. Sites run by a government (.gov), organizations (.org), and educational institutions (.edu) may either have more credibility or less, based on user experience and the diligence of their website staffs.

The secondary suffix (geographical location) may also prompt a closer consideration of information from some sites, because some areas of the world have fewer laws governing the use of the internet.
Social networking is the least acceptable source of accurate and unbiased scientific information. When on social networking, opinions outweigh scientific fact.
internet sites that can be edited by any user are generally not acceptable as a source of accurate and unbiased scientific information. These sites tend to reflect the views of the writers, without any peer review or research.