It has been an extraordinary week for Twitter. On Wednesday, multi billionaire Elon Musk wrote to Bret Taylor, the chairman of Twitter, to make a $41 billion cash offer for the social media company. “Twitter has extraordinary potential. I will unlock it,” the Tesla and SpaceX founder concluded while warning that he would probably sell his 9 per cent share in the company if his offer was rebuffed.  Understandably Musk’s bold move drowned out Twitter’s own announcement the previous day that it had acquired a small Irish start-up called OpenBack.  The price paid by Twitter for the six-year-old Irish start-up wasn’t…