To decide, we must learn about Internet structure and organization. There is so much more than putting words into search engines. We can make some very astute generalizations about a webpage very quickly if we can judge the reason it was published. Not only is this an important step in analyzing any information but this tells us a great deal about the contents of a webpage. Yes, merely determining a site belongs to an association actually specifies the quality, motivation and type of information we will find.
Commercial interests have much more difficulty delivering useful resources.
On occasion, commercial interests will support a worthwhile service tied closely to their own service - thus banks present interest rates and bookstores present their book stock. The certainty with which we can make these judgments will astound you. They simply don't have the motivation. Only an individual would publish this, most likely not on the web but though a mailing list. Information is not distributed randomly.