One thing that I hear from time-to-time is that Yummy, my iPhone application, lacks “polish.” But what do people mean when they say that?

When I ask, what I usually find is that these people have never actually used it. They have probably looked at screen shots, maybe one of the screencasts. They can see that there are few graphics and little animation.

That’s fair — it’s absolutely true — but that’s not what I think of when I think of polish.

Instead, Yummy is designed to be quick and convenient to use. It’s modelled more after Apple’s Contacts app than, say, the Camera or Photos. In this sense, it’s not a few well placed graphics that makes all the difference. It’s the fact that Yummy saves your location in it when you exit ((Of course iOS4 does a lot of this for you now, but I first implemented this when iPhone OS 2.x was current.)), even when you’re in the middle of editing a bookmark. It’s that your searches are automatically saved so you don’t need to re-type terms you use regularly. It’s that you can edit bookmarks even when offline. It’s that if you use a short bookmark (like tinyurl or bit.ly), you can fetch the full URL and the title of the web page.

In short it’s lots of little things that I can’t even begin to list on the features screen in its iTunes store listing. They’re not really features as such, but their absence would make for a much weaker program.

None of these things can be seen just by looking at screenshots. Indeed, some of those refinements may not be noticed at all. But I think it’s this very subtlety that defines polish. Marco Arment touches on this when he says that the best UI is invisible — this is exactly what I was aiming for.