i've had Midomi on my iPhone for quite some time, but had only used it occasionally until I really learned how to use it.
As a bit of a nerd for well-designed user experiences, the most striking aspect of Midomi's UI is its simplicity and versatility. When the app loads, almost the entire screen is taken up by a giant button which you tap to start the process of identifying a song, with some smaller buttons underneath. The relative size of this button correctly identifies its important, because tapping that button start's Midomi's process of listening and identifying whatever sound you give it-- whether it's recorded music, or you singing a song yourself, or even just humming a tune.
If, for some reason, you already know the title and/or artist, the smaller button below is there for you as well, which sometimes comes in handy if you want to bookmark something and don't need to use the listening function.
Its proven to be very useful for "bookmarking" songs I've heard in restaurants, at events, or in the car-- and the ensuing playlist is rather awesome.
Also, because its database is supplemented by user submissions, Midomi is fast and accurate when identifying songs. And with a growing userbase, it's getting better every day.
A great model, great service, and handy and fun to use. Well worth the iTunes store purchase!
