In the academic world it is considered very important that new research builds upon past research and that the quality of information is assured. There are formal processes to facilitate this, and it's essential you understand these if you are to succeed at university.
No standard system of quality control
An expert researcher will make judgements based on the content of the site, and the credibility of the source of the information.
One of the hardest parts about doing academic research on the Internet is figuring out where to start!
A search engine or subject portal is usually the first thing to try, but which are the most useful for your research need?