The perception of the viewer has alot to do with how they perceive the spirit.  As a zen master would say, once Etherial communication hits the human brain, the information received becomes contaminated. 

Isn’t it kind of odd that the examples of shadow people shown in the article resemble Freddy Krugar and the other a mad monk from the middle ages?  Looks like the psychic impressions of the spirits were influenced by the subconscious.

Since you’re so interested, but apparently unable to find examples, please have a look at Electronic Voice Phenomenon Is Not Evidence Of Ghosts , there you will find several examples of very basic experiments pretty much anyone can undertake to utilize the scientific method in pursuit of a better understanding of what EVP might actually be, I mean aside from simply hanging your hat on the unfounded conclusion “that there be ghosts here!”

Incidentally, while I may occasionally suffer pangs of identity crisis, I remain only one person, and as such you may want to adjust your view of who “we” are; the name of the website notwithstanding.  I take your veiled ad hominem insult as a compliment.