The other piece besides focus for execution is intensity. Startups only work at a fairly intense level.

So if you want a culture where people work hard, & pay attention to detail, focus on the customer, are frugal: you have to do it yourself.

Wait to start a startup until you come up with an idea that you feel compelled to explore.

By the way, that's my number one piece of advice if you're going to join a startup: pick a rocket ship.

As the company grows and about this 25 or so employee size, your main job shifts from building a great product to building a great company.

You should think about for the next 10 years, you're going to be giving out 3-5% of the company every year.

The tenth social network, and limited only to college students with no money, also terrible. Myspace had won.