As long as I manage investments properly and don't spend recklessly, Tumblr has given my family a strong safety net and given me the freedom to work on whatever I want. And that's exactly what I plan to do.

Charge for something and make more than you spend.

If you sit on, sleep on, stare at, or touch something for more than an hour a day, spend whatever it takes to get the best.

With Instapaper, I can take a few months off. I can't stop publishing 'The Magazine' for two months and work on something else.

One reason I love the Kindle, more so than the iPad, is that on the Kindle you can't do anything else but read. It's the best, because it does the least. It doesn't even show a clock.

I don't need every customer. I'm primarily in the business of selling a product for money. How much effort do I really want to devote to satisfying people who are unable or extremely unlikely to pay for anything?

Instapaper does support paywall sites. I have a list of them, that when someone saves something it sends a copy of the page as they are viewing it only to them. If you subscribe to a paid site, you can save the content. I'm not really touching the money.