"2. Building on Someone Else’s Platform is Risky"

This is a common mistake. You should only do this if your product/idea is short-term. I would never build a long-term business on Twitter or Facebook, but I see so many people attempting to do this.

If they make a change where you have to pay 10X for access, limit your bandwidth, or even come out with something that directly competes with our product, you are done.