Interview with David Karp: the rise and rise of Tumblr

Tumblr’s popularity is going through the roof. Founder and CEO David Karp talks to Oliver Lindberg about the blogging platform’s recent outages, its rivalry with WordPress and why it’s such a hit in the fashion world

This article originally appeared in issue 213 of .net magazine in 2011.

At the beginning of December, blogging platform Tumblr became too popular for its own good. It had always grown pretty steadily, but what happened in 2010 surpassed anything that ever came before. It started the year serving 100million impressions every month and closed it at three billion. Then it suddenly came to a halt for 24 hours.

“We hit a lot of scaling bottlenecks all at once,” explains David Karp, Tumblr’s founder and CEO. “We’ve always been adjusting and expanding our infrastructure to handle all of this new traffic every month. But in the last few months traffic has really shot up like crazy. We’re now growing at about a quarter of a billion impressions a week. These staggering numbers are frankly outside of what we were expecting! We’d planned to spread out a lot of stuff over a few months — new equipment orders, changes to our infrastructure and databases — but all of a sudden our tag, post and blog databases all hit capacity at once. That pushed us into a very frenzied few weeks of placing huge server orders, doing lots of database work, moving data around, adjusting network and code optimisation …”

Some of this database maintenance took out a database cluster and, because there wasn’t enough capacity to lean on, the rest of the service went down with it. Various blogs, with TechCrunch leading the way, criticised the New York-based startup for its handling of the crisis. It even led to Tumblr getting an official downtime image courtesy of The Oatmeal.

“Actually, we weren’t down for 24 hours straight,” Karp responds. “We slowly won the service back over a period of eight hours that we were completely down. So we were online in parts of Europe before the US and we were online on the East Coast an hour before the West Coast. We also posted every four hours to our Twitter account, which is all we had online to post to, to let people know that there was no data lost and that it was taking longer than we thought it would. The real truth is it’s just incredibly awful and frustrating, no matter how you spin it. Our goal is making sure that nothing like this can ever happen again.”

Tumblr has since opened another data centre, nearly tripling capacity, and is lighting up new servers every week. Some of the $30million of venture capital funding that the company recently raised will be spent on improving the infrastructure. When former lead developer Marco Arment, who single-handedly looked after the technical side of Tumblr for three years, left the company to concentrate full-time on his new project, Instapaper, Karp also decided to replace him with a whole team of engineers who had a lot of operating experience. “He and I were in over our heads but we’ve now brought in a team of nine engineers, who have done this before and know how to design an infrastructure that can scale to this level. They’re brilliant at this type of systems architecture and they’re doing a spectacular job.”

Building something new

Karp isn’t your average entrepreneur. At 15, he dropped out of his New York high school to be home-schooled, went to live in Tokyo on his own two years later and launched Tumblr when he was just 20. He’d wanted to set up a blog but felt that the long-form, traditional editorial of existing blogging platforms such as Blogger, WordPress and Movable Type wasn’t for him.

“I had all these cool videos, links and projects that I wanted to put out there, and I had a really hard time doing it,” he remembers. “I wanted to do something different. I was determined not to compete with WordPress. It’s incredible, and people like Matt Mullenweg are much smarter and more experienced than me. So when we started, we hosted our official blog on WordPress to say traditional blogging wasn’t dead and that WordPress did it better than anyone. But I think there’s a market that wasn’t served by the existing tools. People using WordPress occasionally say they’re moving to Tumblr but I don’t know whether that’s true. We aren’t pulling people away, we’re picking up users that tried the other platforms and found they didn’t work for them.”

Tumblr’s accelerated growth is down to specific communities, Karp explains. In the beginning, avant-garde bloggers joined the service, which meant that sites such as Digg and Techmeme linked to Tumblr. Then, towards the end of 2009, whole universities started to sign up and over the last year the creative community, including notable musicians, photographers and writers, has grown significantly. “We’re starting to get a level of mainstream attention that’s self-perpetuating,” says Karp. “Lots of people tell you that once you enter that mainstream, at some point you cross a threshold and it just takes off.

“I don’t know anything about that, but more and more we’re finding ourselves ingrained in communities and cultures. For example, we saw the Philippines take to us all at once. For the first time, we’re also getting a lot of traction in Germany, France, Italy and South America. They’re brand new markets. Normally they’re in different time zones and the traffic is spread out, but South America is hitting the site at the same time as the US. That’s the other thing that we weren’t really expecting and brought us to capacity a bit sooner than we had planned for.”

One of Tumblr’s biggest communities is the fashion world. It’s so important that Tumblr has recently hired a fashion director, Rich Tong, founder of social fashion site Weardrobe, which was snapped up by Google last year. The company also sent more than 20 bloggers to New York Fashion Week in February.

“I have no clue about fashion,” Karp admits. “That’s one of the reasons that one of our first specialised community people is on the fashion side. Someone that really speaks the language, has the vocabulary and can reach out to people to find out why they liked Tumblr, so we can do an even better job for them.”

Community reaction

Karp reckons Tumblr is popular among fashion bloggers because they get a lot of reactions from the community. “There are low-level actions such as Liking, Replies and Answers and very high level actions such as Reblogging that mean talented, creative people get picked up by much bigger audiences than on traditional platforms. It’s a really good fit for that community. The average WordPress blog is getting 0.85 comments per post, and on Tumblr the average is 3.8 interactions per post. So, if you figure out how to hustle and create stuff that the community loves, you get tons of attention.”

So more community managers will follow, as will custom tools around film festivals and fashion events to aggregate all the activity within the community. However, Tumblr remains opposed to advertising on the site. The startup makes money through a marketplace of premium themes and by charging users for promotion in its directories.

A major overhaul of those is in the pipeline. “We want to tweak them to be more about content, so that people work as hard as they can to create great stuff that bubbles up to the top rather than just pay to promote their blogs. The directory will be much more dynamic and useful. It’s the place to see the most interesting design and fashion content from the entire community. And if things are too new or have slipped through the cracks, users or brands could pay to show their stuff up there.” Tumblr is currently testing the new directories at and

Meanwhile, Tumblr has opened a new office for its mobile team in Richmond, Virginia, which is feverishly working on a new iPad app and revamps of the iPhone, Android and BlackBerry apps. Karp expects to make around 70 new hires this year, thus more than tripling the size of the company. For Tumblr, it seems, the only way is up, and this time round Karp’s team might just be ready for it.

In 2013 Yahoo acquired Tumblr for $1.1 billion. Karp remained CEO of the company. As of 1 May 2016, Tumblr hosts over 292.7 million blogs.

This article originally appeared in issue 213 of .net magazine in 2011. Photography by Daniel Byrne.