Steve Jobs famously said that great artists steal, and the company has often taken that mantra to the extreme over the years. Some would say that much of Apple's current software bears more than a passing resemblance to some of its competitors' products.
Take iOS 5's Notification Center, for example. You'd need to be blind to say that it does not look eerily similar to the same notification system that Android has packed since day one. Some would argue that there are only so many ways you can handle something like a pull-down notification window. Some would call it stealing.
Apple has even taken some cues from its own App Store. Mobile Safari now sports a "Reading List" feature that offers a similar service to that of Instapaper, the famous web app that also has a popular iOS app in the App Store. Instapaper's developer, Marco Arment, doesn't seem too concerned, but others were not so happy...