This September I had the pleasure of listening to Jeff Veen (of Adaptive Path - now Google - fame) talk at the dConstruct conference in Brighton. His talk was mostly to do with interface design choices on the web, but a lot of it is universally applicable, even outside of the web.

One of the great things about Jeff is he's able to bring in seemingly unrelated subjects and demonstrate how they are metaphors for the decisions and problems we face on a daily basis. So when he started talking about one of his favourite book - "Sea Kayaker: Deep Trouble", it might initially have seemed like he was digressing in a big way, but it actually contained a very pertinent message.

The book is a collection of stories from sea kayakers who've gotten into life-threatening situations, so as to help you learn from their mistakes. Jeff quoted one important line from this book:

"Obeying rules without an understanding of the reasons behind them creates an approximation of competence which leaves one vulnerable to the exceptions."

The point I'm somewhat laboriously trying to make here is that simply copying a good design from somewhere else won't necessarily solve the problem. In fact, it's only likely to work if what you're creating is actually identical to whatever you're copying. If you're making an online bookstore then copying Amazon makes sense, but that doesn't mean it's even remotely sensible for a website selling cars.

Unfortunately, programmers who copy design patterns for UI from programs they like aren't necessarily even choosing the good stuff. They're more likely to copy features which suit their own needs (as how else are they likely to appreciate them?) rather than those their end users will find of benefit.

So, to cut a long story short: don't just copy. Find out what works best for your specific users, and do that instead.