There are many signals of likely truth or falsity that can be verified algorithmically by a computer, often more quickly and thoroughly than they can be verified by humans:
Does the story or graph cite any sources? If no sources are given, it is far from certain that the story is false, but the likelihood increases that it should be investigated further. Note how the fake story with which I opened this article provided no sources, and how it was debunked by Snopes by finding the actual sources of the graphs.
Do the sources actually say what the article claims they say? For example, it would have been entirely possible for Business Insider to claim that the data used in their article was from the FBI, but for there to be no such data there, or for the data there to be different. Few people trace the chain of sources to their origin, like I did. Many propaganda and fake news sites rely on that failure to spread falsity. Checking sources is something that computers are much better at doing than humans.
Are the sources authoritative? In evaluating search quality over the years, Google has used many techniques. How long has the site been around? How often is it referenced by other sites that have themselves been determined to be reputable? (Google’s PageRank algorithm, which revolutionized internet search, was a variant of scientific citation analysis, where the importance of scientific papers is evaluated by the number of other papers that reference it, and the reputation of the individuals or institutions making those references. Previous search engines had used brute force matching of the words contained in a web page with the words that the user was looking for.) Most people would find the FBI to be an authoritative source. We don’t think about the tacit knowledge that lets us make that determination, and might be surprised that an algorithm lacking that knowledge might still be able to come to the same conclusion by other means. Yet billions of people have come to rely on Google’s algorithms to do just that.
Some opinions expressed in this article may be those of a guest author and not necessarily Analytikus. Staff authors are listed in http://www.datasciencecentral.com/profiles/blogs/how-i-detect-fake-news-1