The World Wide Web is full of websites that may or may not be of any use in your research. How can you tell whether you're looking at a good source or a bad one? Here are some tips:
Look at the name: Take a look at the url (web address) - what is the domain? Typically .edu and .gov websites will have stricter guidelines about what can be published and by whom.
Find the contact information: Authors love to be recognized! When you put a lot of work into finding and synthesizing information for publication, you want people to know who you are, or at least the organization you wrote it for. Be wary of websites with no way of contacting the creators.
Look for sources: Good researchers, even when writing informally, will cite their sources. This may be a link embedded in their post, mentioning the source by name in the content, or a more formal footnote or list of works cited. This gives you the opportunity to read the original material and see if you come to the same conclusions!