The more I use the iPhone/Touch user interface with various apps, the more I appreciate the well-designed apps and get frustrated with the ones that are poorly designed. I get the impression that some people think that the superior design of the device itself makes it impossible to create bad designs. They're wrong. There are numerous instances of problematic designs. The example I'd like to provide here is one poor design within an app which I find to be otherwise fairly well designed. See the image to the right. It is the status update screen within the Facebook app. The problem with it is the placement of the primary action buttons "Cancel", "Clear", and most seriously "Post" which submits the update. The problem is that the button is placed right above the "O" and "P" keys, making it all too easy to hit the "Post" button in error. When you do hit it in error, you've then submitted your status update and it is sent out to everyone of your Facebook friends. The design that works much better is to have the primary action buttons placed above the entry field. This is just one of many instances like this where designers need to take into account the fact that users have to use their fingers which differ quite significantly in size from one user to another. Making an error such as hitting one alpha key instead of another while annoying can be easily corrected and often is by the software itself. However, the placement of buttons that yield direct actions which can't be undone should be examined very carefully. Only designers that have experience with Kiosks have had to deal with these types of problems in the past whereas now all designers of mobile apps have to take these sorts of issues into account.