F*** yeah! Tumblr CEO's delight as he announces $1.1 BILLION dollar deal with Yahoo! after Marissa Mayer promises 'not to screw it up'

• David Karp founded Tumblr in his mother's Manhattan apartment in 2007
• He thanked users on staff blog on Monday for their support, saying: 'We won't let you down'
  
• Yahoo! CEO Marissa Mayer believes purchase of micro-blogging site will be a 'stake in the ground' for her tenure as head of the tech giant 
• Site boasts 100million users and 90million daily blog posts

By Louise Boyle and Michael Zennie

Published: 10:35 EST, 20 May 2013 | Updated: 14:27 EST, 20 May 2013

David Karp, the 26-year-old who has just sold his fantastically popular blogging site Tumblr to Yahoo! for a $1.1billion cash deal, made the announcement today and signed off with a resounding 'F*** yeah'.

Karp, a high school drop-out who started the site from his mother's New York apartment in 2007, posted a message on Tumblr's staff blog on Monday.

He told users that he was 'elated' to be joining Yahoo! and echoed the words of the company's CEO Marissa Mayer by saying: 'We won’t let you down.'

Scroll down for video, full statement and gif

F*** yeah! David Karp, who founded Tumblr in 2007 in his mother's Manhattan apartment, just sold the site to Yahoo for $1.1billion

Success story: David Karp dropped out of high school but founded Tumblr, a wildly popular micro-blogging site which has turned him into a multimillionaire

He wrote that Tumblr's vision 'to empower' users had not changed but that he was excited to have the help of Mayer and the Yahoo! team.

In closing, Karp wrote: 'As always, everything that Tumblr is, we owe to this unbelievable community. We won't let you down.'

The casual 'F*** yeah', a somewhat brash sign-off to a billion-dollar deal, is reminiscent of another tech tycoon's attitude to the world of multinational corporations.

Mark Zuckerberg once touted Facebook business cards with the words 'I'm CEO, B****' emblazoned on the front.

Karp's announcement came after Yahoo!'s board of directors agreed on Sunday to buy the wildly popular blogging platform Tumblr, which boasts 100million users and 90million posts per day, for $1.1billion cash.

The deal makes the native New Yorker the latest 20-something tech tycoon, even though he was publicly opposed even last year, to selling the company which he founded in his mother's small Manhattan apartment in 2007.

However, Karp - a high school dropout who taught himself how to code - had expressed grave reservations about giving up his brainchild to a Silicon Valley tech giant.

In a 2012 interview with the Guardian, he said he had been swatting away buy-out requests for years.

'Particularly in the first three years, there were a lot of (mergers and acquisitions) people who would pull you aside and you'd think "Well, s***, I could be a pretty rich 23-year-old with very little effort,"' he said.

'We stuck it out. I won't say I really knew why.'

Moving on up: Karp lives with his girlfriend Rachel Eakley, a graduate student and chef, in a modest apartment in Manhattan's West Village

Big deal: The $1.1billion takeover of Tumblr is Marissa Mayer's major move since she took over as Yahoo CEO in July. Observers say she is using the deal to set the tone of her tenure at the company

Perhaps the perseverance makes sense to Karp now that he is 'very rich' at age 26.

The deal conjures images of another young man who is very rich - Facebook founder Mark Zuckerberg.

Legendary: Facebook CEO Mark Zuckerberg's former business card also to a flippant approach

At $1.1billion, Tumblr's worth is nowhere near the value of $100billion Facebook, but 29-year-old Zuckerberg's success has become something of a pattern for young, brilliant tech entrepreneurs.

It is unclear how large a stake in the company Karp maintained before the Yahoo deal.

In 2008, he sold a 25 per cent stake to investors for $750,000. 

The investor share of the company was $125million at the time of the deal, according to AllThingsD.

Karp grew up on Manhattan's Upper West Side, the son of a music composer father who wrote songs for films and TV shows and a mother who was a teacher.

He taught himself how to code HTML at age 11 and began setting up his own consulting business shortly thereafter. His parents allowed him to drop out of high school at age 15 and complete the remainder of his education by home-schooling.

At age 17, he moved to Japan, where he cemented his skill as a programmer and began pitching his ideas to tech companies.

He moved back to New York and sold his services as a consultant. He founded Tumblr in 2007 at age 21 - and it quickly consumed all of his time.

He started up an office in Manhattan and has ardently resisted the lure of moving to Silicon Valley. He also tried to resist the money that the tech world had to offer.

He told the Guardian that he wanted to remain independent - believing he could grow the company by growing ad revenue naturally.

Within a year, though, he was accepting funds from venture capital investors.

He currently lives with his girlfriend Rachel Eakley in a modest apartment in Manhattan's West Village. Miss Eakley is a chef and a graduate student studying psychology.

Miss Eakley has been Karp's constant companion at public events for several years

On Monday morning, Yahoo! CEO Marissa Mayer publicly announced the purchase of Tumblr with a post on her own Tumblr page - including an animated GIF image that acknowledged the public questions about the acquisition.

Her first words about the deal were: 'We promise not to screw it up.'

Mayer announced that Karp will stay on as CEO of Tumblr and continue to run and develop the site.

Despite a massive user base, Tumblr's revenue was only $13million last year. Even that figure was only made possible after $125million in capital investments.

The deal also faced almost immediate backlash from Tumblr users, who feared Yahoo!'s ownership would change the character of the site and water down the features that make it successful.

Mayer sought to allay concerns on both sides - and even used an internet meme to make light of the criticism. The GIF she posted reads: 'Yahoo. Tumblr. Now Panic and Freak Out.'

Instead, Mayer urged users and Yahoo! investors alike the 'Keep Calm and Carry On' - a reference to a famous British propaganda poster produced during World War II.

Tech news site AllThingsD reports that Mayer, who took over as Yahoo! CEO in July, wanted to quickly snatch up Tumbler as 'the stake in the ground of what her strategy is going forward for Yahoo.'

Tumblr, which is a mico-blogging platform for quickly posting pictures, text and video, also functions as a social media site.

Its platform manages to blend elements of all of the major social networking sites. Sharing and posting photos is simple and easy, like Instagram. GIFs and videos are all easy to share, as well. But, the site also has a new feed function, allowing users to follow other Tumblr blogs like social media networks Facebook and Twitter.

Very young and very rich: Karp and Eakley, who enjoy spending their Sunday mornings at brunch in Manhattan's East Village, are now due for a major lifestyle change