When you encounter any kind of source, consider:
Evaluating internet sources:
The internet is a great place to find both scholarly and popular sources, but it's especially important to ask questions about authorship and publication when you're evaluating online resources. If it's unclear who exactly created or published certain works online, look for About pages on the site for more information, or search for exact quotations from the text in Google (using quotation marks) to see if you can find other places where the work has been published.
Adapted from Evaluating Resources. Berkeley Library, University of California. https://guides.lib.berkeley.edu/evaluating-resources#authority