Uber's valuation in particular worries me. Uber's product is 90 pixels on your phone - that's it. Behind that is computer code and an admittedly powerful networ

Uber's valuation in particular worries me. Uber's product is 90 pixels on your phone - that's it. Behind that is computer code and an admittedly powerful network effect among drivers and riders. But I have to wonder about that power of that network effect over time, especially with this race to develop self-driving cars and other similar things. Meanwhile, Uber's business practices are, shall we say, often times questionable. Customers increasingly dislike the product, whether it's surge pricing, or dirty cars, or lousy drivers. I just get nervous by these companies whose products are a single app on your phone and some computer code. This is generally not a great setup for being worth a lot of money 20 years from now.