I guess I am strange. The first one was kind of hard to see, but I got it, after that I saw multiple answers and tried to choose the strongest one. The Last one I did get though. It is the only one I saw clearly.
Well, it is just one of several sites to scare someone. I saw another one where there was a large image (picture of a room) and you were told there's something completely wrong with the picture but it would be hard to find. Then after some time a huge scary scull looking face appeared with a loud scream.
I showed it to several friends and noticed two different reactions, some got scared the crap out of them, others didn't even flinch and thought it wasn't that funny.
What I noticed between these people was that those who actually went closer to the screen, actually trying to be careful to see something, were best audience. Those who just casually looked at the screen and weren't that involved didn't get much out of it.