65,000 skins, they say. That’s extraordinary, especially considering how creative and well done many of them are. MySpace was an even bigger creative explosion of customization.
What’s the next product that will inspire this kind of user ownership through theming? Allowing it isn’t terribly difficult. You allow people to write (or link up) their own CSS and, ideally, give them sensible selectors to hook onto.
Be careful you don’t open up any XSS holes. The much harder trick is building something that people want to skin. Once you’re over that hump, it’s about having enough people theming it that it starts to inspire other people to do the same.