David Weinberger: Everything is miscellaneous.
(Somehow it seems fitting to link to the blog rather than the Amazon page here.)
Weinberger argues (and here, for once, I can say that I have been there as well) that with the Web and digital, searchable information, we can rely on categorization less. We can move everything into the category "miscellaneous" and establish order by search, metadata extraction, etc.
The book lays out a detailed and very well written argument. I my summary seems overly short, it is because many of the ideas were familiar to me – but Weinberger writes beautifully, yet tersely, and this will, no doubt, be a standard reference for years to come.
Highly recommended!
Chapter summary (very short):
Chapter 1: The new order of order
Chapter 2: Alphabetization and its discontents
– alphabets are arbitrary, and alphabetization took a long time to be adopted
– topic-based ordering fails because of disagreements about order and the rate of change of knowledge
Chapter 3: The Geography of knowledge
– lists (the first order of order)
– Dewey decimal system
– knowledge is evolving, so system quickly becomes outdated
Chapter 4: Lumps and splits
– trees (the second order of order)
– Linnæus
– facet-based ordering (Colon Classification)
Chapter 5: The laws of the jungle
– tags (the third order of order)
– del.icio.us and Wikipedia
Chapter 6: Smart leaves
– metadata application; identification by UPC, RFID, tags
Chapter 7: Social knowing
– recommendation engines
Chapter 8: What nothing says
– metadata generation
Chapter 9: Messiness as a virtue
– semantic web too ordered, Flickr is a better metaphor, include and postpone
Chapter 10: The work of knowledge
– how the work of knowledge is changed, things defined directly in terms of their relationship to other things
– include and postpone, order applied later, emergent order
Coda: Misc.
Applied Abstractions 
Such an excellent book deserves a longer review than a bullet point enhanced table of contents posted here 🙂
But the summary may be made even shorter: Don’t let constraints of the physical world limit how you organize digital information. . This has sometimes been referred to as the Shirky/Weinberger principle.
Readers of this blog will probably appreciate these two videos:
Weinberger’s 1 hour lecture at the Google HQ
http://video.google.com/videoplay?docid=2159021324062223592
Michael Wesch: “Shirky/Weinberger the Movie”
href=”http://www.librarything.com/thingology/2007/10/shirkyweinberger-movie.php
Harald,
thanks for the comment – yes, I agree, but this is less a book of new ideas than an excellent collection, systematization and rearticulation of them. Hence, achieved chunking means that I can make do with a shorter list….