Twitter shares remained strong Monday after Friday's sharp rise on reports that it was considering a possible sale, with Google parent Alphabet and Salesforce emerging as two of the most likely buyers. Twitter for more than a year has faced enormous pressure, both internally and from investors, to consider a major shakeup. It has struggled to find ways to monetize its core 140-character microblogging property to achieve convertible streams of revenue, while rival Facebook has continued to grow engagement and develop new revenue streams.