I remember sitting around the lunch table in a tech company when Google IPO'd and none of us understood the IPO valuation. I didn't buy any stocks. I also didn't get "cloud" either. Sometimes new business is essentially created out of thin air. Google and Amazon's valuation did not increase only due to their efforts, it also increased because the broader market shifted.
I guess that means don't take investment advice from me ;) I've done OK buying indices though.
The fact that Wall Street sometimes misses revolutions and misvalues stocks does not mean that all perceived misvalued stocks are revolutionary.
Plenty of companies have screwed up execution, and the market has correctly noticed and penalized them for that.
Reading through this news article is hilarious.
P.S. I did not have access to internet in 2006, so I guess the skepticism was normal at the time.
So, to help you understand how they can be true: market cap is governed by something other than what a business is worth.
As an aside, here's a fun article that embarrasses wall street. [0]
[0] https://www.nbcnews.com/id/wbna15536386