President Obama -- Rubbing Elbows at Fundraiser ... With Tumblr CEO

The guy who created Tumblr is hobnobbing with big wigs after selling the company to Yahoo for $1.1 billion ... something he proved by sitting next to President Obama Thursday at a fundraiser.

The duo was at an intimate fundraiser this week in New York at the home of a big time investment manager ... which means Tumblr CEO David Karp made a good impression last month when he interviewed the prez.

Karp and Obama didn't talk much at the fundraiser, according to the NY Post, but they discussed all sorts of things during the interview ... including how to pronounce GIF.

Sorry Tom from Myspace.