By Alexei Oreskovic and Jennifer Saba (Reuters) - Yahoo Inc said it is buying blogging service Tumblr for $1.1 billion cash, giving the struggling Internet pioneer a much-needed platform in social media to reach a younger generation of users. The deal, announced on Monday, is a bold bet by Yahoo Chief Executive Marissa Mayer to revitalize the company by co-opting a Web property with strong visitor traffic but little revenue. Yahoo made clear it was sensitive to concerns that it might damage Tumblr by making it less irreverent or more corporate. ...

By Leah Schnurr NEW YORK (Reuters) - Stocks were little changed on Monday as acquisition activity gave support but investors were reluctant to rush into the market with indexes hovering around record levels. Deals including Yahoo's $1.1 billion bid for Tumblr indicate that companies continue to search for growth through acquisitions, a bullish sign for stocks. Yahoo was up 0.8 percent at $26.73. The S&P 500 and Dow industrials finished Friday at fresh record highs and the Nasdaq Composite is at its highest since late 2000. ...

(Reuters) - Dell Inc said in a letter to suitors Carl Icahn and Southeastern Asset Management that the company would not provide more information about itself unless the board determined that their proposal was "superior" to founder Michael Dell's. Earlier this month, Icahn and Southeastern offered $12 in cash per share or additional shares to existing investors as an alternative to Michael Dell's $24.4 billion bid to take the company private. ...