First of all, pretty much everything is overvalued in the markets right now. What is the MOST overvalued? e-commerce by far. Take a look at this.
The last red line in the chart is e-commerce. Stocks like Amazon have no correlation to their bottom line, and the stock prices do not represent the value of the company.
Stocks like Netflix, Amazon, Snapchat, Facebook, etc...
As interest rates rise, pressure will likely squeeze these companies first. Tech stock/e-commerce bubble provides a huge chance to short a market that is topping.