My personal opinion is that the bubble was created by the telecommunication infrastructure expansion/buildout. When this came to an end, a significant economic stimulus was removed. In comparison to past bubbles, created by other infrastructure creation and expansion, (electrification, telephone, automobile/highway,) this expansion occurred in a relatively short period of time.
I have not fully studied the collapse after other infrastructure buildouts, however, I believe that those comparisons will yield valuable insights into what we can expect.
