[kobeya]

Nearly all of Silicon Valley post-2001 is either (a) online retailers/ecommerce, or (b) parasites hanging off of the $100+Bn/yr online advertising industry. At the top of that latter food chain sit only a handful of companies -- Google and Facebook being the big ones. So much of everything you see in IT and tech in general, from the IT worker to the graphic design consultant to analytics and "big-data" machine learning startups are living off of money that came from clicks on ads or checkout carts at buy-and-ship retailers.

Facebook "only" took in around $26Bn in advertising revenue last year. But their ads are considered more reliable and higher quality than Google's products, so admit some speculation about growth potential. With a global advertising market (across all mediums) of half a trillion dollars that is quickly moving into digital, is it any surprise that these top dogs have high P/E ratios? Those P/E's are based on anticipated future revenues, shares of a pie that is rapidly expanding in size. Comparing P/E using earnings of this year doesn't give the full picture.

That said, they're certainly not undervalued either, and this analysis does nothing to explain Amazon (WTF is going on there? Surely they don't have $200bn of inventory and warehouse property. Do they?). But 35 P/E is only 3.5x more than the 10x rule of thumb, and the entire market could reasonably grow by that amount. That appears to be what investors are betting on too.

(If I had to turn this into stock picking advice, I'd note that if the market is predicting the future accurately here, then one can also say that traditional non-digital advertisers aren't going to do well in the years to come [no surprise], and also that general tech will likely see a huge influx of revenue and capital investment as the top dogs trickle down their market share gains. Baring some black swan catastrophe things will likely be good in Silicon Valley for some time to come, even outside of the FANG companies. But you should not take this as investment advice, which I would not be qualified to give, etc. etc.)

ETA: For the record there's a third prominent SV category I forgot to include in the list, which is peer-to-peer services. AKA the sharing economy. AirBnB, Uber/Lyft, Instacart. Part of why these were so exciting in the last two years or so is because it was a gold rush on new markets that hadn't been colonized by tech companies yet. Doesn't really affect this comment in any way though, other than technical accuracy of that sentence.

[andrewjl]

Interestingly the exceptions to this rule, namely companies with $1B+ valuation, are almost all HQed or originally started outside SV.