There are three overriding categories of photographs that people seem to consider
ghostly: blurry people in motion, long exposures in which a subject (or the photographer) moves into the shot and pauses before moving away, and cemeteries. There were also at least three images of jellyfish in the first 400 listed that I looked through as I endured a slow day at work yesterday.
While I was flipping through them, one-by-one, using the link viewer, iTunes shuffling in my ears,
this page came up just as "Clocks" by Coldplay began and I felt the song — particularly the intro — fit the image perfectly.
So when I got home -- at 2 a.m. -- I set up the tripod on the balcony and shot a few 4-second exposures of the abandoned ALCOA factory adjacent to the cemetery next door. It's the factory moreso than the tombstones that I wanted to capture.