Have you come from the future? If you want your secret to be preserved, be sure to not Tweet about it. Physicists from Michigan Technological University have started searching for signs of time travellers on Facebook and Twitter.
Astrophysicist Robert Nemiroff and physics graduate student Teresa Wilson have been trawling through social media posts around either the discovert of Comet ISON in September 2012 and the election of Pope Francis in March 2013, to see if any evidence of time travel exists. With this information, they're looking for any content containing "Comet ISON," "#cometison," "Pope Francis" or "#popefrancis" that was posted before the events happened, as according to their paper this may very well be a time traveller.
According to Nemiroff and Wilson, they found "searches on Facebook turned up results that were clearly not comprehensive." Maybe people of the future have more of a grasp on privacy settings than we do? No signs of time traveller life were found on Twitter either, unfortunately. But never fear, just because the two didn't see any time travellers doesn't mean they don't exist.
The two researchers conclude it may not be possible for time travellers to leave evidence of their journey behind. Namely it "may be physically impossible for us to find such information as that would violate some yet-unknown law of physics," or even they don't want to be found and "may be good at covering their tracks."