It still could have been prevented. I'm not saying the websites or administrators should be held responsible, but if you post empty suicide threads on the internet, you're clearly begging for attention and you've clearly got some issues. Both of these things seem to apply to this guy, and they were ultimately the reason why he killed himself. He had issues that he did not get help with. Now his family and his kid are going to have to pay for it. It's pretty tragic, in my opinion.

EDIT: I watched the video in the first link. WTF is that thing they threw on him? It looked like they were tazing him.

Also, while I don't think the websites or administrators should be held responsible for anything, I do think that something should happen to the people who were egging him on to kill himself. As much as I love the internet and places like /b/ on 4chan, sometimes shit crosses the line, and this is one of those times. Stuff like this is giving the internet a bad reputation.