I see them, too. Actually, I talk to them, though that sounds completely bonkers. They're like us; not completely good or evil. I've actually adopted their religion because I find it so full of thought and knowledge. They talk about "shadowy entities," too, but they seem to be one of the major causes of the people seeing shadow people.
I remember when I was a freshman in high school, there was one shadow person who had followed another person to school that day. He was in a particularly playful mood, but with nothing to do (obviously). He saw a few boys playing around by the lockers (which he was "perched" on top of) and was watching them try to steal this boy's coat or something -- don't really remember too well, but they were playing rough. Some other boy walking by (don't remember who any of them were) saw the shadow man and froze, and when the man had got the attention he got excited and darted down. He stole the bigger kid's backpack, gave it to the frightened kid, and pulled him (he was making his run). It was very funny, but none of those kids had any idea what happened.

I have been seeing them all my life, but I learned that they spoke when I was older. They reminded me of deer since they always ran away when I looked at them, so I figured I could give them names. When I did, one of them actually gave me her name, very excitedly but shyly. I learned that she was young (probably mentally near my age at the time) and that her favorite color was green "with orange spots in it."
Another time, I was alone in the woods. I do this often, and sometimes I end up with company, as I did this time. However, this time the shadow person wasn't in a good mood, and as they are very quick I couldn't get away from him. Luckily for me, he left me alone after that. (Supposedly he isn't allowed to come back, but who knows what that means.)
Most of the ones I have met have been pleasant, though. They're very interesting people. The thing is even though I know for certain that they are accountable for most of the shadow people stories, they know about other stories like the "Hat Man." They have an "answer" to his existence... but who knows its accuracy.
Most are friendly, I think. But... well, I don't know where I'm trying to go with this. Get some sleep?

They're mostly nice, and the ones that aren't don't really feel like they can hurt you. Don't worry.