When looking at websites online, it's important to evaluate the quality of the source.
The CRAP tool is one way for you to evaluate websites and other sources you may come across during your research process. CRAP stands for: Currency, Reliability, Authority, Purpose.
Check out this guide to evaluating sources for more information.
Keep in mind that the quality of a source is relative and can depend on your information needs. If you are not sure about your source, contact a librarian or your professor.