Currently, I haven't seen any overwhelming proof of a bubble (the type of proof that no one can dispute). Without said proof, it's up to everyone to digest their information and make their own opinion. It's only an opinion and until you can over conclusive statistics that sway a large majority of educated people, why waste your words? If you work at LinkedIn, this article becomes only slightly relevant to you (you may be out of a job in the future etc.). If you don't, this sort of thing should be ignored and you can continue to work on your business.

There is no bubble for solid (market-validated) business plans with reasonable, actionable revenue models.