One problem with using social media to get your news is that sometimes news that aren't really new start being spread on a social media. If the news item is sufficiently catchy it can get huge attention in a short amount of time. This is a problem because repeated exposure to a news item tends to make people less critical and to believe that the news item is trustworthy. If all your facebook friends post the same item you assume that they cannot all be mislead. The mistake here is that all your friends don't independently do background checks but rather just re-tweets or re-posts something they have heard elsewhere.
One month ago my wife called me to tell me about a study they had just talked about on the radio (thankfully, this was not the publicly funded radio which would have been very disturbing). According to this study, done by Dr. Weatherby, watching big boobs on a regular basis could add several years to your life. Dr. Weatherby, a Harvard medical scientist published this paper in the prestigious journal: New England Journal of Medicine.
So what is the problem with this? The problem is that it is completely made up. There is no study and there is no Dr. Weatherby! Indeed, this particular story first hit the media in 1997. Back then it was published in a newspaper that publishes funny, but fictional, stories. However, since this original publication it has been re-published several times, apparently by people who thought that there was a real study. Following these re-publications, the story has then gone viral which in turn lead to occasional mentions in uncritical mainstream media outlets.
A few days back another similar thing happened here in Sweden. An article from 2008 about the black widow spider having established itself in Sweden was shared a few times on facebook. Because it was not mentioned (perhaps because it was not noticed) that the article was old, people assumed that it was fresh news. Soon it was all over facebook. According to one report I heard it was shared more than 200000 times. Some Swedish newspapers jumped onto the train and published versions of the 2008 article as if it was fresh news. They had clearly not done their research since even a simple background check would be sufficient to discover the problem.
For all of those who simply skip to the last paragraph (like I do sometimes), looking at big breast does not increase your life span and the black widow spider is not established in Sweden.