Just a day after Twitter announced that CEO Dick Costolo was stepping down , a Harvard Business School professor said the company needs a "clean sweep" to prevent a total downfall.

Bill George, a Harvard professor who was formerly the CEO of Medtronic and sits on the board of directors at Goldman Sachs and ExxonMobil, said Twitter needs to speed things up quick.


George, like many others, called for Costolo to resign months ago amid the company's struggles to grow its user base . He said Twitter is at risk of following BlackBerry's path- from a leader in the industry to obsolescence."They haven't even appointed a search committee until now," George told CNBC on Friday. "What are they doing? The world is passing them by."

"Twitter is rapidly becoming the BlackBerry of social media," he added.


George joins the many critics who say that the company's issues stem from it's board of directors and said Twitter should look at Google and Facebook's example of bringing on innovative leaders from the outside in order for the company to grow in new ways.

"But if they continue on the way they are, this does not bode well for Twitter at all," George said. "I see them in the same malaise they've been in the last five years."

He also said that the company's interim CEO, co-founder Jack Dorsey, needs to be out quick.

However, many people, including Business Insider's Henry Blodget believe that Twitter isn't gearing up for a fresh start and that was Dorsey really wants to become the permanent CEO of the company.


You can see George's comments below.

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