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.