Some things that make a website reliable are the source of the published information, the date the information was published and the credibility of the publisher. Credible sources include established organizations and recognized authorities in specific fields. Current content is a must, as old information can become invalid.
Commercial sites are not always trustworthy sources of information, as some businesses put an inaccurate slant on content in an effort to make sales. Bias is also often found on news and political websites because many reporters put a personal spin on facts. It is also a good idea to be wary of amateurishly designed sites, though not all poorly designed sites have unreliable info.