Facebook can leverage Messenger Kids to influence the 13-and-under crowd so that when they turn into teenagers, they are drawn towards Facebook's ecosystem of apps and not towards Snap Inc (NYSE: SNAP ). That will erode the equity risk premium, drive inflation higher, and dilute the present value of "down-the-road" profits, which is where these hyper-growth stocks get a ton of their value from. This makes sense, but it ignores the fact that these same hyper-growth tech stocks will also get a huge earnings boost as a result of the tax bill.