Izik was built from the ground up for the tablet experience and offers a highly differentiated and intuitive search experience. The product was built by Blekko, which also offers a traditional desktop search experience "the spam-free search engine", as well as Rockzi, which is a highly visual (think Pinterest-like) social news/hobby board. According to Quantcast, Blekko has 1.8mm US unique visitors (Quantcast says DuckDuckGo has 248k monthly US visitors), so it could be called a large niche, or tiny mainstream player.
Unlike Blekko, Izik really is different; it saves clicks.
I suspect that if someone is going to really mount a serious search threat to Google's search position, it will have at its core a fundamentally different user interface. Microsoft won the application marketshare race by leveraging Windows, Apple's resurgance is, in a large way due to its smartphone's use of touch, and I am sure there are plenty of other examples, like Pinterest, where a fundamentally new approach to the user experience changes markets.
With Siri, Apple is betting that verbal commands will be at the core of a new user experience. Moreover, we are already seeing how mobile apps are changing the search paradigm as in-app search efficiency saves so much time/clicks that users don't think about exiting an application, such as Flixster, to search for movie or theater information.
Hopefully, for Google shareholders, the company is not getting too infatuated with self-driving cars, or with replicating many Kansas City wired experiments. It seems as if the times are changing in the core business.