OK, just a note. Rumours of Kim Jong-un's assassination have been floating around on twitter all night. These originated on Sina Weibo, the local twitter plus service, on Friday morning after a load of police cars were seen outside the DPRK Embassy in Beijing. That relates it back to the Wang Lijun case, which broke when the cops began showing up outside the US consulkate in Chengdu. The Kim rumour flashed across Weibo and then got taken up by Chinese twitter users, who seem to have spread it West.
The significant point about this is that it's the first case I can think of where something that originated in the Sinosphere breached the Firewall and caught on outisde in any substantial way. From Beijing's point of view, that's going to be a security breach.
Obviously, we can discount the rumour itself - except that it's now been out for 15 hours, with nothing to squash it. But no doubt that is a function of how Pyongyang works, or fails to work.