No source of information is 100% reliable. The great convenience of the Web comes with a price. It's very easy to post wrong information. Our own site has had its share of errors, especially in our early days. A scan of other Q&A sites shows an enormous range of reliability, sometimes even within individual sites. Many posted answers on some sites are completely wrong. We try to avoid that by having two or more people go over each answer, and by urging you, our readers, to write in if you find anything that looks wrong. (To let us know about an error, just submit a follow-up question to it.) We believe we've now reached very high reliability.
One way that you can try to get more reliable information is to use a range of sources—different internet sites, books and articles, knowledgeable people you know, etc. If they disagree, you can consider which ones are the most logical, have the most convincing evidence, and have the best track record. When it's possible, nothing beats being able to do an experiment, observation, or calculation yourself!
Meanwhile, we hope to stimulate a little improvement of some sites with our new feature:
in which we will give examples, with explanations, of incorrect information posted on the Web. To be featured on our Baloney page, published Web info must be seriously mistaken, not just slightly misleading or controversial or off on some detail. We hope some of the sites whose answers we feature choose to edit or remove them. We invite everyone to send in suspected Baloney examples, from our site or others.