Change the world. Build a business. Have fun.

I suspect there's a lot of validity to the premise that big companies aren't going to attract entrepreneurial talent.

After high school, I enrolled at the University of Nebraska at Lincoln, but I stayed only a year and a half. I felt college was a waste of time; I wanted to start working.

I tried to be a ski bum when I stepped away from Twitter, and I wasn't a very good skier.

User experience is everything. It always has been, but it's undervalued and underinvested in. If you don't know user-centered design, study it. Hire people who know it. Obsess over it. Live and breathe it. Get your whole company on board.

Every major communication tool on the Internet has spam and abuse problems. All email services, blogging services and social networks have to dedicate a significant amount of resources and time to fighting abuse and protecting their users.

The things that keep nagging at you are the ones worth exploring.