But instead of trying to pry him away from his machine or coaxing him outside to get some fresh air his mother Barbara Ackerman had another solution she suggested that he drop out of high school to be home schooled.
I saw him at school all day and absorbed all night into his computer said Ms. Ackerman reached by phone Monday afternoon. It became very clear that David needed the space to live his passion. Which was computers. All things computers.
Now 26 years old Mr. Karp never finished high school or enrolled in college. Instead he played a significant role in several technology start ups before founding Tumblr the popular blogging service that agreed to be sold to Yahoo for $1.1 billion this week. With an expected $250 million from the deal Mr. Karp joins a tiny circle of 20 something entrepreneurs hoodie wearing characters like Facebook s Mark Zuckerberg and Foursquare s Dennis Crowley who have struck it rich before turning 30.
When I first met David he was 20 years old and wearing sneakers and jeans said Bijan Sabet a general partner at Spark Capital who was one of the first people to invest in Tumblr. But I knew he was one of these rare entrepreneurs that grew up on the Web and who could come up with an idea build it himself and then ship it that night.
Since founding Tumblr six years ago Mr. Karp has been admired for his programming skills and Web site design acumen but at times has been a polarizing figure in New York tech circles because he so often blogged about his personal life and party hopping. He has popped up in the New York Post s Page Six Magazine and has been a recurring target for the gossip Web site Gawker where he was labeled a fameball a derogatory term for someone who has an unquenchable desire for fame.
Tall and willowy with a mop of brown hair and piercing blue eyes Mr. Karp typically dresses in jeans a T shirt and sneakers. He speaks at a rapid clip and often for minutes without stopping. Technically he never graduated from high school which he cracked in an interview is hopefully not a condition of Yahoo employment.
After dropping out and working for a time in small New York tech outfits Mr. Karp made his way to Tokyo where he worked for several months for a start up. He returned to the United States and became the chief technology officer for UrbanBaby an Internet message board for parents. CNET Networks bought UrbanBaby in 2006 and Mr. Karp took the several hundred thousand dollars he made from the sale to start his own company called Davidville. One of Davidville s projects was a simple blogging service called Tumblr.
Mr. Karp s run at Tumblr has not been without problems. He had trouble hiring in Tumblr s early days unsure how to even interview recruits. He often thought large companies were too big for their own good proclaiming he could manage Tumblr with a team of four.
But Mr. Karp stepped out of the party scene and started dating his current girlfriend a graduate nursing school student at New York University four years ago. He also appeared to get more serious about his company as it grew from less than a dozen employees to more than 175 today. David has grown up in Tumblr said Mark Coatney who oversees Tumblr s relationship with media companies.
Still Mr. Karp s unsure footing led to discussions about his taking a different role at Tumblr according to two people who worked with the company and who agreed to speak on the condition of anonymity. Because revenue was not growing as fast as they would have liked investors considered putting Mr. Karp in charge of Tumblr s product development and finding a more seasoned chief executive.
Mr. Karp denied in an interview that there was a plan for him to give up the chief executive s job. He said that when Tumblr s chief operating officer left in the middle of last year filling that job and other critical roles like head of marketing was top of mind but he said there was no plan for him to step aside.
Like many who run so called social Internet companies Mr. Karp can teeter on reclusive. In an interview last year at the F.ounders conference in New York he said he preferred to come to the office early to work alone avoiding other people.
Where I feel the most productive and engaged is when I m buried in code buried in some project tweaking some designs he said. I m certainly introverted.
Nicole Perlroth and Michael J. de la Merced contributed reporting.