Clear, the new todo list iPhone app from Realmac software, got a lot of buzz thanks to very impressive demos during Macworld in January. Interest in the app was so high that at least one opportunistic ripoff artist copied Clear wholesale and put a copycat app on the App Store before Clear even debuted. Our own review of Clear found that its simple but intuitive interface definitely lived up to the weeks of hype, and in my own usage I've found Clear an invaluable tool for organizing my day.
It turns out Clear has been extremely successful so far, having sold 350,000 copies in just nine days according to The Guardian. Those are extremely impressive numbers for a simple todo app; Clear joins Epic Games' Infinity Blade and its sequel as two of the few apps I've heard of that have gained so many new users so quickly.
Widespread press coverage, a low introductory price of US$0.99, and Apple featuring it as App of the Week on the App Store helped propel Clear to the success it's seen thus far. Realmac isn't resting on its success, though; an update to the iPhone version is in the works, and Realmac confirmed to The Guardian that iPad and Mac versions will follow. Realmac is "open to the idea of taking it to other platforms" -- Android and Windows Phone 7, in other words -- but they reiterated that Apple's devices are their first priority.
If you haven't checked out Clear yet, I highly recommend it if you're looking for a simple todo/list maker app with a streamlined interface that doesn't get in your way.