Hmm, interesting link.
I've seen shadows all my life. Since I can remember. From men, to woman, to farm animals, to house pets.
Some call the people "shadow people" and from my personal experiences, they have never meant me no harm.
I see then straight on, or out of my parariphial (sp?) vision. So I just call them "observers"..
I can sense the deceased. They can come from beyond they veil at times, or sometimes they never got to go beyond it. They simply want to be here and "oversee" what's going on.. Or they miss a loved one.. Or they got lost...
The reasons are endless as to why some "observers" are here.
Now, some people see another force .. These so called "shadow people" with other that benign intentions. I've never ran across one, but I have ran across some nasties. They don't look like shadows to me. Their forms are distorted, and quite frankly, if you haven't seen them, can frighten you.
I've seen them often, and use tools to keep them at bay til they get bored. Or I use banishing rituals if I see they won't give up.
(a rarity, they get bored easy sometimes) well, some do, some dont.
REMEMBER, salt is your friend. And it's cheap. Bless your water. Remember iron, just in case they shapeshift from Fae, set up mirrors in prime spots of entryways (doors, windows) in your home. And sweep, and clean, and cleanse your home often. Smudge as often as possible.(4-6 weeks is my ritual, ans I sprinkle salt after I smudge)
Use these tools if you feel threatened... This is easy stuff.
Also, if you haven't, make a witch's bottle and place it in the land or deep in your home if needed.
I haven't looked up too many banishing spells, because I frankly believe the ones that come from you work best. HOWEVER, if you need a place to start, look up a few to get a good idea to set up to get on the right track, if you feel threatened.
Some of those nasties can take over your life.
I hope I helped.