Oh, the irony -- Microsoft has spent $600 gazillion to market its Windows Phone 7 devices and is paying $1 billion to Nokia to get the foundering phone maker to adopt the low-capability OS. But it's been outsold significantly by a mobile OS you never heard of: Samsung's Bada.
According to data from market researcher Canalys, in the first quarter of 2011, Microsoft's hardware partners sold 2.5 million Windows Phone 7 devices worldwide, of the 101 million smartphones sold in total. Samsung's Bada-based line of Wave smartphones sold 3.5 million units in Europe and Asia, despite tepid reviews. (For the record, 36 million Androids, 24 million Symbian devices, 19 million iPhones, and 16 million BlackBerrys were sold during the same period globally.)
About a year ago, Samsung decided to open-source its proprietary cellphone operating system, resulting in Bada (Korean for "sea"). Samsung uses it in its Wave devices, and that's pretty much it. Bada is also a very limited mobile OS -- I hesitate to call Wave devices smartphones, as Bada units aren't much more than the "feature phones" that existed before the iPhone arrived: mobiles with a few primitive apps such as games. But it is more than those devices, offering a real Web browser in addition to social neworking clients and a smattering of feature-phone-style games and apps.
Bada is meant to appeal to those who don't want their phone to be a computer, but do want to access the Web and keep in touch with their friends via Facebook and Twitter. There's no notion of security or enterprise manageability -- no business would consider a Bada device to be anything other than a cellphone.