You might have seen those status messages on Facebook where your friend says they want to stay privately connected to you. Or the BBM broadcast about cosmic rays from Mars. Or the message that Yahoo! servers are full, and unless you forward a certain message, your account will get deleted. Sadder still are the messages that say things like “For each person you forward this email to, XYZ Corp. will donate USD 0.01 to ABC”. I remember a tweet about an accident on the Third Mainland Bridge in Lagos, which I shared, and was later proven to be mostly untrue (the accident did in fact occur, but nobody ended up in the water).
It might be spitting into the wind and being overly obvious, but we really should realize that we shouldn't trust everything we read or hear. Some things are people's opinions. Some of them might be mistakes. Some, like this post makes clear, can just be from people taking advantage of other people's emotional responses to what they read (by the way, I think the post's author is making a very valid point).
At the very least, mention while sharing that something has not been verified. That should give people's natural cynicism a chance to kick in. And avoid blowing up (especially for effect) whatever you choose to share. If you heard that three cars crashed together, resist the impulse to exaggerate. When it's bad news, bigger is definitely not better. Panic over exaggerated claims often causes much more damage than the actual event itself (anyone remember the explosions in Ikeja Cantonment some years back?).