They say "experience is the best teacher," but that only works for us as individuals. Though we will take action as a group, we will generally learn alone. That's why collected "best practices" and consultants' reports often ignore

• the mistakes we learn from
• the shortcuts we use to make our jobs easier
• the hidden steps that lead to breakthroughs

As individuals, we can learn even these things from relationships with more experienced mentors. As an organization, we need a different tool. One such tool is the learning history -- a chronicle of some project's development that includes the personal views of the participants and commentary from whoever is maintaining the chronicle. The learning history has the following benefits:

• permits by definition narrative and commentary
• raises issues that might otherwise not be discussed openly
• builds a "learning environment," where everyone who participates in the project learns lessons from the chronicle

Other ways soft knowledge can be retained in an organization:

• some overlap of skills and responsibilities (though you have to be careful to have workers avoid competition and "reinventing the wheel," this overlap allows for real-time instruction)
• some organizational rotation through different functions (not just within engineering, but also through marketing, sales, field service, etc.)
• eliminate discrimination in information access (i.e. let everybody have the same access to the knowledge that's there)
• have a vision that's open-ended (though the products still get out the door, the organization isn't limited by policy in what it's allowed to learn)
• remove obstacles to individual and group goal-setting
• support reasonable risk-taking
• allow reflection, analysis, and trial and error (and teach techniques for time management so critical paths aren't hurt by learning)

Individual responsibility in the spread of soft knowledge includes

• admit our mistakes when they occur
• separate criticism from judgment (criticism places responsibility for action, and even blame, on others; judgment only recognizes the need for action)
• recognize that, while diversity alone does not ensure creativity, a group with similar backgrounds and interests will generally allow only "comfortable" ideas to pass through it
• recognize our own individual learning and communication styles

References

Harvard Business Review on Knowledge Management. Boston: Harvard Business School, 1998. ISBN 0-87584-881-8
Kidder, T. The Soul of a New Machine. Back Bay Books, 2000. ISBN 0-31649-197-7