I saw the original Japanese version of this movie called Kairo. It was creepy but you really didn't have any idea what was going on. The American version isn't really creepy but you have a pretty good idea what's going on.
Significant parts of one became minor parts in another. Events depicted by cutting away and back were redone with elaborate special effects. The original takes the philosophy that we're all alone when we live and all alone after we die. The new one takes the approach that everyone, even the dead, have a drive to live.
Both movies tell the story about the dead using the internet to come into our world. Once you see the webcams of people committing suicide you're pretty much screwed. You're supposed to close off a room with red tape. In the original it seemed like whoever did that was summoning the ghosts but that could be part of my confusion because it was a way to protect yourself in the American version. Together they make for a decent movie but neither one by itself is worth a damn.