Jeff Oxenford tells an entertaining quick story about Capturing Knowledge (attempting to) from his 7-year old daughter and her fun science project. Tears ensued, passion waned. Redemption at the end.
This speaks volumes about capturing knowledge. Next time I think about how great it would be to capture tacit knowledge, I will remember this example. Writing things down is difficult to do and especially hard to capture the excitement. It's much easier to verbalize what you know, it's more interesting, and a much better way to exchange knowledge.
Letting people talk (or write) about the things they are excited about is a great way to communicate and share what they are doing. This also implies that people are passionate about what they have done.