Zuckerberg stressed that entrepreneurs need to give themselves the flexibility to follow what they learn, and what they love:

“I have this fear of getting locked into doing things that are not the most impactful things you can do.  I think people really undervalue the option value in flexibility.  One of the lessons is…do something fundamental. A lot of companies I see are operating on small problems, and that’s fine if you want to be an entrepreneur, but the most interesting things operate on a fundamental level.  Companies getting started now that are just trying to copy what other people are doing aren’t successful.”