There has been an interesting discussion on Linked-In, debating whether it is better to create knowledge depositories around organizational units (divisions, teams, branches) or specific subject matters.
My view is that organisation by subject is far the better way, for 5 main reasons
1. Part of the value of Knowledge Management is enabling knowledge to be shared across organisational units. Imagine a manufacturing function divided into regional units. What is the point of organising knowledge by unit? Teams within the regions have a closer working relationship already than teams in different units. Far more value is to be gained by exchanging knowledge between units.
2 . Organisational structure changes on a far more frequent basis than topics/subjects.
3. The real value of knowledge management comes when discussing know-how. A subject equates to a practice area, which equates to know-how. Hence the value of developing Communities of Practice, which create, share, apply and steward the development of practice know-how. Communities of Practice are a fundamental of KM; communities of organisational unit are not. The top level taxonomy of your knowledge base should equate to your CoP structure, which should equate to your list of strategic knowledge topics.
4. Arranging the content by Subject will make it easier to demonstrate compliance with ISO 9001
5. People seeking for knowledge on a topic will not necessarily know which organisational unit has sourced the knowledge. Imagine looking through a library reference section, where instead of organising the reference books by topic (gardening, cooking, sport) they organised them by the author's home town!
Having said that
a) your knowledge base should be arranged by Subject but also tagged by operational unit (and by contributor) to allow search by whichever method is needed,
b) your larger knowledge management framework needs elements that apply within the organisational unit (AARs, KM plans, lessons capture, KM champions) and elements that apply across units (CoPs, Lesson-sharing, knowledge bases, SMEs, Practice Owners)
c) there are organisations where the Subjects should be organised by Practice, others where the Subjects should be organised by Product, and some where the Subjects should be organised by Customer (see here).