No, you guys are idiots and are reading just the headline.
Child pornography is sick and vile, however, so are people on the Internet, therefore, the two mesh quite often when you wonder into dark corners, but this ruling does NOT in any way legalize the possession of child pornography.
This decision was made to protect those who get exposed to this content beyond their knowing. With the current law, I could email you a picture that would be considered illegal, and you would go to jail. Under this ruling, it protects you as long as you don't save it and immediately erase it.
I'm going to leave this unlocked because I like the potential for discussion here, but please read all the facts before commenting. This does not in any way say that child pornography is legal to possess, you will do hard time.
For my opinion, this is fantastic. I've read many stories in which people have been stuck in jail for years because they visited a website which hosted child pornography and yet there were no traces on their computer, the simple fact that he had been on the website called him guilty. Who would a jury side with? Even if they guy is completely innocent and had no intention of harming anyone, no one on the panel wants to defend an alleged pedophile.