Microsoft announced today that the Xbox One has sold over 2 million units in its first 18 days of being on sale. Microsoft's Corporate VP of Strategy and Marketing for Xbox, Yusef Mehdi, said that the system is sold out at most retailers in its 13 launch markets.
"We're also particularly excited to see consumers engaging in a wide range of games and entertainment experiences on the platform, with more than 1 million paid transactions on Xbox Live to date."

To compare, the PlayStation 4 sold 2.1 million units within 18 days of its initial release in North America.