I found this article on one of the paranormal websites.

What is a shadow ghost/person? Are they evil? I've been doing a bit of research on the subject...this is what I found: Shadow ghosts (or shadow people) are usually ghosts but dark in color. They can be dark grey, brown or black and usually have no distinct features, though there have been many accounts of shadow ghosts/people with shining red eyes. Some have a human figure and shape, others appear as a dark mist. Most are seen with black hoods covering their 'heads'. Others are just a dark blob or mass... Even though the descriptions of this type of ghost may vary, two things are commonly found on all reports. The first is that they are seen out of the corner of a human being's eye, or they are 'glimpsed' at and when the person turns, blinks his eyes or tries to get a better look, they can see nothing. The second thing is that they are dark, where other ghosts or spirits are whitish, transparent, or may have features and a bit of color. Many people think these beings are evil in nature. This is not true. Shadow ghosts aren't evil just because they are dark. They just choose to manifest themselves with a dark ectoplasm. I read somewhere that it is much like when a living person chooses what color of clothes to wear. I don't know if this is true, however, as I've never interviewed one!:) I've seen a shadow ghost twice. Once when I was out for the evening with some friends and I was coming back home, I saw a lady, I say it's a lady because it seemed to be wearing a long dress, with some kind of shawl over her head. She wasn't very tall and seem to float or glide (no feet either) very fast into the house where I was living at that time. I saw her out of the corner of my eye, and when I turned to see who she was, she was gone. The second time, I saw the same figure again... same shape and all! And also out of the corner of my eye...fleeting glimpse and gone. Shadow ghosts have also been photographed, but are very rarely caught on film. Have YOU ever seen one?

http://www.ghostsamongus.net/v2/Content/pid=6.html

I too see them head on. I have also ruled out any explanation as to why, other than that what I'm seeing is that of a shadow person.

No problem. And Undead Elf, I didn't mean for my post to come across harsh. I am very passionate about the paranormal, and get excited easily. A fact my wife just loves about me. Shadow being sightings that are head on are quite common. The black mass at Waverly is a prime example. This thing not only is seen head on, but sometimes by large groups of people.

I've seen them head on as well.

I actually find them the most interesting thing that I have run into so far (in the realm of the "paranormal")