Choice architecture is not about nice buildings. It's about encouraging people to do stuff; the architecture of choice. Not a new concept by any means - the entire ad industry is based on it. There are some wonderful examples of how behaviour can be influenced in VW's The Fun Theory website. My favourite is the bottomless trash can. Originally designed to stop people dropping litter, it was so successful that folks actually went around looking for rubbish to deposit.
Choice architecture is also a central component of the UK Coalition Government's 'Big Society'. For example, encouraging individuals to volunteer in local initiatives, something that could never be coerced or mandated. Thaler and Sunstein's book 'Nudge' uses some interesting examples from organ donation and energy consumption to illustrate how our lifestyle choices are subtly, but deliberately, being influenced by government policy.
So how does Choice Architecture relate to Organisational Learning and knowledge sharing across firms? Well, the verbs encourage, persuade, influence are central. This is neatly reflected in Dave Snowden's heuristic of "Knowledge will only ever be volunteered it can not be conscripted". We need to be cognizant of the fact that, irrespective of corporate edicts about collaboration, or investment in web2.0 technology, every individual has a choice in whether they share or not.
My boss in a previous job used to talk about 'the pain principle'. If something is easier (or in the case of the trash can, more fun) to do the new way, it is more likely to happen. If it is more difficult, or a pain, it won't. Every intervention, technology, policy or tool we develop should be subject to the Choice Architect's slide rule; 'is it easier, quicker, less costly or (heaven forbid) more fun for the individual than the old way'? At this level, 'easier' probably trumps the others.
I am amazed at how many change programmes and technology projects miss out on applying this simple test.