People put up web pages for many different reasons.
The trustworthiness of information may be affected by the motivation of the person or group sponsoring the web page. Every page represents somebody's opinion, but some are more opinionated than others. It is important to be aware that the information you find is representative of the author's point of view. Remember, you need to get everyone's point of view. If all of your sources represent the same opinion, you may have a problem.