In other words, if the information you find does not make sense, given your existing knowledge base, or runs counter to what you have already discovered, this should be a warning, telling you to begin questioning the reliability of what you have found.
However, you do not have to rely solely on your own knowledge. In addition to the hints provided above, you might also want to consider whether the resource is up to date, uses appropriate sources, and has active external links to the nformation sources used.
You might also consider factors such as the design of the page and the care with which the article has been presented and structured. If these basic aspects of the site are not reassuring, then you might want to consider what this tells you about the care with which the authors may have put together their arguments or indeed the importance they attach to the document (Cameron 2001).
Finally, it is often useful to look for any indications that anyone else has evaluated the information before it was placed online. If the document has gone through a peer-review or editorial process (as is generally the case with journal articles published online, newspaper articles and official documents) it is far more likely to contain accurate information than sites that have been placed directly on the web by an individual or advocacy group, with no internal or external check.