Yahoo Promises Not to "Screw It Up" Over 1.1 billion dollars Tumblr Deal. Guardian May 20th ,2013 Yahoo promised "not to screw it up" as it formally announced its acquisition of the Tumblr blogging platform for 1.1 billion dollars ahead of the US stock market opening on Monday. The deal, which is expected to complete in the second half of the year, is almost all cash, is equal in value to Yahoo's money in hand at the end of its first quarter in March but it has substantial extra assets in short-term securities, shares in the Chinese site Alibaba, and other equities which it can liquidate. Yahoo plans to use its personalization and search technologies to tie Tumblr users more tightly into its network