Sources say the boards of both companies have agreed to the buyout. It will be announced Monday at an event in New York.
Yahoo! Approves $1.1B Tumblr Acquisition
The Yahoo-Tumblr Deal: Why They Paid $1.1B
YAHOO BUYING TUMBLR
President Obama's Tumblr Q&A at the White House
Yahoo buying Tumblr for $1.1 Billion