I think The Blair Witch Project had a huge impact in all the "ghost hunting" channels and shows out right now.
And the extent to which ghost hunting has become an amateur activity on social media platforms is like an indication of the diffusion of the aesthetic, narrative, technological, and performance traits and techniques seen in that film.
As @chrstphrolson points out, shows like The X-Files helped instill the ideology and narrative that "the truth is out there." And, of course, without social media and digital camera, we won't have so much footage with people seeking celebrity, either for "real" or "fake" ghosts.
And, like, I KNOW I shouldn't take on a new project, but these are some of my favorite things to talk about, and now I just want to do interviews with these ghost hunters and paranormal investigators to understand how they make sense of what they do and what led them to do it.
Because (heavens help me, I really am thinking about it) this also aligns with fan studies and the idea of fandom inspiring presumption as a form of fan labor or fan activity. ARGH...