Anyone can publish information on the Internet -- which means it's a reader's responsibility to determine whether the information they've found is both reliable (worthy of trust) and valuable (useful for their needs).
When you have to make an important personal life decision, you don't believe and act on the first piece of advice that someone gives you -- especially if that person isn't someone you know and trust. You should handle your information needs with the same caution and skepticism.
When you encounter an idea that someone has put out into the world, always ask yourself: should I believe and act on this?
Don't trust a source based solely on the site's appearance. It's easy to make a site look professional.
Don't automatically trust a .org site; don't automatically distrust a .com site. It's easier than you think to get a .org domain. And many credible sources operate under a for-profit model.
Don't rush your research. Fact-checking takes a little extra time; there's no way around that. Getting credible sources will require a minor amount of legwork.
When you find something on the Web, always ask yourself :
Answering these questions won't always lead you to a guaranteed, concrete judgment about the source -- but you will likely be on the path to a critical evaluation.
Is this a new and unfamiliar source? If it is known, trusted, and reliable, it's probably OK to continue. If it's not, then it's important to pause and think about how to fact-check this information.
What can you find out about it elsewhere on the Web? Even a quick search to see what other sites say about this source can be helpful. Wikipedia can be especially helpful for this kind of investigation.
Is a known, reliable source covering this topic? If you are uncertain about the reliability of a found source, look for information on this same topic, event, or issue that comes from a trusted source instead.
Can you find the origin of this information? Every time information is reported by a source that's not the original, there is a chance that it could be misstated or misrepresented, accidentally or deliberately. Going to the original source is the best way to find information that is complete and unaltered.
(Adapted from Mike Caufield's Check, Please! Starter Course)