Ofcourse Platform companies are overvalued. There is no real tech here just user content they are trying to monetize.

Infact I would go ahead and say real tech was under valued look at Sun Microsystems, A company that Developed its own Processor (Sparc) , Its own OS (Solaris) , Its own Database (Mysql) , Its own VM (Virtual Box) , Its own Language and Development Platform (Java), Its own Development IDE (Netbeans) every one of those products is real technology and a leader in its own category.

And yet the company was sold at 1 Billion USD, which seemed like short change.