Yahoo's board has agreed to buy Tumblr, the popular blogging service, for about $1.1 billion in cash, a person with knowledge of the agreement said Sunday.
The deal, sealed at a meeting of Yahoo's board, is expected to be announced as soon as Monday, said the person, who was not authorized to speak ahead of the announcement.
The acquisition is the biggest yet under Yahoo's chief executive, Marissa Mayer, as she attempts to reinvent the once-embattled Web pioneer's fortunes.
Under her, the company is seeking to make up for years of missing out on the growing use of social networks and mobile devices.
Buying Tumblr is intended to help address thatshortfall. The 6-year-old company is one of the most popular blogging services, with more than 108 million blogs.
Buying the company could provide a wealth of user-generated content.
The acquisition will be a test for Mayer, who will have to ensure that Tumblr does not get lost inside Yahoo. In the past, acquisitions made by Yahoo's former chiefs, including Geocities, an early social site, and Flickr, the popular photo-sharing website, have either been shuttered years later or neglected within the company.
Yahoo and Tumblr have been in talks since last week trying to finalize details of the acquisition. Facebook, Microsoft and Google all showed interest previously in purchasing Tumblr, an employee of Tumblr said, but those talks never culminated in final offers.
Tumblr was founded in February 2007 by David Karp, who is 26. According to the company's latest statistics, Tumblr has 175 employees and has raised more than $125 million in venture funding from several big-name firms, including Union Square Ventures, Spark Capital and Betaworks. It is unclear if all of the company's 175 employees would become Yahoo employees, too.
The deal was first reported by the technology news site AllThingsD.