Everything is miscellaneous. Sounds obvious, right? Boring, even. If it weren't for rave reviews from some sources I respect, I never would have picked up this book. And I certainly wouldn't have made it past the first few pages, which discuss the finer points of silverware drawer organization. But I have a neurotic tendency to finish books I start - and I liked Weinberger's previous book - so I kept with it.
By the end, Weinberger completely dissects the implications of the title. Everything is miscellaneous, so don't try to categorize. Put all your information in a giant heap, attach simple metadata (tags) to elements that you find interesting, combine it all, and let the web sort it out. This is the secret behind Flickr, Google, Amazon, and zillions of other extremely useful, innovative, and seemingly magical web sites. The power to sort through miscellaneous, unorganized data is a new phenomenon, powered by the internet, and is quickly replacing previous organizational methods that were built to organize objects within limited physical space (such as the Dewey Decimal System and the card catalog system).
This is a wonderful book for anybody designing software, a process that inevitably forces the designer to decide how best to store information and display it to the user. Weinberger provides a clear answer: organize minimally, if at all. Let customers define their own categorizations. Provide few limitations. Create an easy-to-use, simple, enjoyable experience. The better the experience, the more customers you'll attract. The more customers you attract, the more information they'll give you. The more information they give you, the more useful the information becomes. The more useful the information becomes, the more powerful your application becomes. The more powerful your application becomes, the more customers you'll attract. A virtuous cycle indeed.