Gold will be indicated to be in a bubble when humans stop trying to impose their will on their little worlds and adopt a new way of doing business. It would appear that the forces in play right now are the levers that apply this pressure. But I think we are still quite some time from finding our way.
Meanwhile, there is scheming in Europe, scheming in Japan and I would imagine a hell of a lot of back room scheming going on in the US. As for this chart why, it pays to remember that when adjusted for official inflation (let alone actual inflation), it looks nothing like this.
Gold haters (aka those that have been afraid to buy all the way up from 300) use this under performance as a means to slam the metal that really is nothing more than a barometer of the times and an insurance policy against monetary abuse.