Because people using Quora think very highly of themselves, and when you have all these people that all think very highly of themselves and each other concentra

Because people using Quora think very highly of themselves, and when you have all these people that all think very highly of themselves and each other concentrated in a single place, then they all think this is a very special and valuable place indeed. This would not mean much in general, but I am willing to bet that most of those Quora investors are also Quora users so they suffer the delusion too.