Investigate the possible bias of the author. Through a background check or prior knowledge, you can determine whether an author or sponsor might have a bias. Check to see if the language free of emotion-arousing words and bias.
If there is advertising, determine whether it is clearly identified and separated from information content.
Examine the website to see if it presents more than one point of view about the topic.
Never assume that extremist points of view are always easy to detect .
Consider these examples:
Is this site objective? http://www.fairus.org/site/PageServer?pagename=iic_immigrationissuecenters6ce3
How about this one? http://www.martinlutherking.org/
Is this medical science or a product promotion? http://www.lucidal.com/