Uber is getting richer and richer. It's now valued at $51 billion after raising another $1 billion in funding, and it got to this stage two years faster than Facebook did. As always, the ride-sharing service has attracted an assortment of investors during its latest funding round -- one of them's none other than tech juggernaut Microsoft, according to The New York Times and The Wall Street Journal. While neither company has admitted it yet, Bloomberg says Microsoft has agreed to back Uber to the tune of around $100 million. It's unclear whether this means they're pursuing a deeper relationship or if they're working together on a project or two, at least. If you recall, though, Uber's snapped up a portion of Bing's mapping tech back in June, along with a hundred of Redmond's employees.