anachronism

Via Boing Boing, a physics professor and a graduate student have embarked to scour the Internet in such of evidence for visits from time-travelers.

They employed parameters that would point to prescience, either direct or indirect that suggest a fore- knowledge, inquiries whose parameters seem to defy causality and too I suppose people claiming to be from the future were investigated. The study found no conclusive evidence, with the admission that this does not prove or disprove anything. Some thinkers postulate that it would be impossible to travel backwards in time to a point before said conveyance, the time-machine, had been invented.  The thesis too has a limited scope, aside from trawling the Internet for clues, in that it only looked for tourists to the past—not individuals native to it and traveling to their future.
I wonder if there might be some similar paradox at work that makes those living in the present somehow blind to things anachronistic—or to view them as a genre, like retro, steam-punk or Gothic, or that time-travelers from the future have returned to the past but to a parallel reality that we cannot experience directly, only as said trends from an alternate dimension.  Widely publicized time-traveler conventions have been held by academic institutions since the 1980s but have apparently failed to attract any genuine venturers. There is also the possibility that stealth and caution have made such journeys impossible to detect—at least through tried means, and maybe time-travelers only need the projects and papers of a professor and his companion like this to tip them off and allow them to cover their tracks.