Android is a strange beast. While it's a Google pet project, its success is more of a result of its hardware partners - most notably Samsung. Statistics on Android OEMs show that Samsung is overwhelmingly dominant, displacing former giant HTC. But, Samsung has been in a bit of a competition with Google as of late. Samsung clearly does not enjoy being tied to Google's services, and it might be looking to move away from the search giant.
Samsung, Intel, Huawei, and Vodafone are putting money behind another mobile OS. Tizen is an open source platform based on (you guessed it) Linux. Allegedly, it's very flexible and supports HTML 5 apps in addition to other cross platform technologies. In fact, its support for HTML 5 arguably makes it more flexible than Android. However, Samsung is the only manufacturer of a Tizen device - the NX300 - a mirrorless camera.
The question remains, will Tizen take off as a serious competitor to Android?
As Nick Sarafolean notes in an Android and Me article, Samsung phones have become almost as synonymous as Apple's iPhone. One can see them everywhere. Right now, Galaxy phones run Android, but they might not have to.
But an Android world without Samsung is entirely plausible. With Samsung being one of the biggest backers of Tizen, they could have plans to leave Android for Tizen, their own operating system that could also be used by others. It’s practically a formula for taking off in the mobile world. With Samsung having even more power over the software of their devices, they could push out updates quickly and easily tie in their own services to Tizen. Samsung already has the web of services to help start their own operating system. They even have their own app store, although it’s rather barren.
Sarafolean also points out that Samsung could split the difference and continue to make Android phones while also supporting Tizen. This could work out if Samsung slowly shifts itself to Tizen. If Samsung does move to Tizen it will be a big blow to Android, for many consumers don't even associate Samsung with Android and will simply move to the new platform unwillingly. Such a scenario could create considerably more competition in the mobile space.
The obvious downside to Tizen is the limited ecosystem. Google has built an platform with Google Play that many tech pundits argue rivals, or even surpasses, Apple's rich ecosystem. Obviously Tizen, like Windows Phone, would have an uphill battle on its hands. In addition to HTML 5 support, it would have to offer a powerful value proposition in order to convince developers to port their apps to yet another platform.