DAVID KARP

People tell me I need an assistant, but I don't want one.

I've found that if you're not responsive to e-mail, it trains people to leave you alone.

I never spent much time with people my own age.

Today there are millions of people making stuff and putting it into the world: that's become part of our identity and it shouldn't be limited to people who fancy themselves writers, or who are particularly witty or talented.

There are a lot of rich people in the world. There are very few people who have the privilege of getting to invent things that billions of people use.

I always carry my camera with me.

Reading for me will be a combination of books, magazines, Tumblr and just kind of the Web in general on the iPad.

I want to build something I'd be happy to be employed by 10 years out.

I'm very antischedule. Except for board meetings, I don't really schedule things or keep a calendar. I think appointments are caustic to creativity.

Where I feel the most productive and engaged is when I'm buried in code, buried in some project, tweaking some designs. I'm certainly introverted.

You guys are more talented than anyone in the Tumblr office or in Palo Alto or Sunnyvale. We're constantly in awe, constantly in service.

Entrepreneur is someone who has a vision for something and a want to create.

We couldn't be happier with our Storyboard team's effort.

Every feature has some maintenance cost, and having fewer features lets us focus on the ones we care about and make sure they work very well.

Our team isn’t changing. … And our mission – to empower creators to make their best work and get it in front of the audience they deserve – certainly isn’t changing.

For every new feature we add, we take an old one out. A lot of big sites don't do that, and it's a problem.

For every new feature we add, we take an old one out. A lot of big sites don’t do that, and it’s a problem. Twitter started as a beautifully simple product, but it’s now going the same route as Facebook. The drive to innovate can overencumber and destroy a product.

Good products are built by people who want to use it themselves

The biggest lesson has been the importance of constantly repeating the mission. It means bringing the team together every week to talk about all of our projects, progress, and vision.

Find a space where you can be creative and a place where you are open for free thinking, you want to enjoy what you are doing and do what you are best at.

Rituals, even unhappy ones, provide a measure of comfort. Like a superstitious ballplayer who will only use certain bats, my depression rituals have become a fixed, normal part of my life. ... I need rituals to prevent unnecessarily rocking my already shaky emotional boat.

We're not motivated by money. We are into this thing that we're building.

The more people we have on our team. the less room there is in the elevator and the more complicated everything gets.

Tumblr was simply a tool for anyone to make a blog like mine.

I think appointments are caustic to creativity.