Credibility

Credibility indicates whether the author and publisher seem reliable.

Does the writer have credentials that give you confidence that he or she is an expert?

Is the publisher reputable? (On the web, publisher means which organization hosts the web page. This is often difficult or impossible to tell. More on that in a moment.)

While the credentials are important, it doesn't mean a source is correct. It's one indication that it is more likely to be reliable. For "serious" topics, credentials are usually an important factor.