SAN FRANCISCO, Sun May 19, 2013 - Yahoo Inc's board has approved a deal to buy blogging and social networking site Tumblr for $1.1 billion in cash, the Wall Street Journal cited people familiar with the matter as saying on Sunday.

Such an acquisition would be Marissa Mayer's largest deal since taking the helm of the once-iconic Internet company in July 2012. Yahoo is keen on fast-growing Tumblr because its younger user base would bolster the older website's "cool factor," the technology blog AllThingsD cited the sources as saying.

Mayer, who spent 13 years at Google Inc, is trying to revitalize a former Internet powerhouse that in recent years has struggled with declining business. On its home page, Tumblr says it hosts 108 million blogs, with 50.7 billion posts between them.

Yahoo declined to comment, while Tumblr did not respond to requests for comment.

The deal comes after a recent failed attempt to buy a controlling stake in French video site Dailymotion, owned by France Télécom SA.

Tumblr, one of the more successful Internet start-ups out of New York, has only just begun earning revenue through advertising. On its home page, Tumblr says it hosts 108 million blogs, with 50.7 billion posts between them.

Yahoo has invited press to an event in Manhattan on Monday at which it promised to "share something special," without elaborating.