The article below contains such bad advice that the only reason I'm posting is that you might come across it, but my hope is that you don't follow it.
1. You cannot "force" people to tell you what you think you need to know. You cannot conscript knowledge (refer to David Snowden and others). Some work activities allow workers to share more than they know - that discretionary contribution beyond what is needed to process the transaction or complete the activity does not so easily occur by management edict.
2. People will just as easily shut-down regarding contributions to a knowledgebase as they will contribute. If they believe that what-they-know is the only reason for their continued employment, and the culture has turned unhealthy, they will view open sharing very skeptically. Workers are not so naive as to recognize that they only reason you're being nice to them when layoffs are being rumored is to trick them into helping you out.
3. Rewards at this point (amidst layoffs, rumors of additional reductions) will result in as much garbage information as anything of value. Suddenly implementing reward and incentive systems while treating workers poorly will be viewed as an obvious ploy.
4. Harvesting email in hidden ways will just cause people to use other channels and taint any trust employees might have had with management.
So what do you do? For some organizations - those with cultures that are already viewed as unhealthy by employees, then there's very little, if anything, you can do from a management perspective - you are reaping what you have sown so to speak. You can improve data/information management and hope for the best. But suddenly "finding the light" in terms of treating your workforce in a respectful manner is going to come across as very self-serving when you do it only in bad times and revert to original bad behaviors in good times.
For organizations that have healthy, or reasonably good relations with its workforce, then there are things you can do. A lot becomes with communication, engagement, shared decision making - options like a reduction in hours or freezing salaries across the board to show shared burdens. Leadership also comes into play. I remember a Hartford, CT CEO who was quoted in the local newspaper (and I'm probably paraphrasing), "If I wanted loyalty I'd own a dog." That type of arrogance and belittling of employees killed any change of people rallying together and helping to rebuilt a sense of community within the enterprise. Condescending attitudes on the part of management are not going to cause workers to participate/contribute with any type of knowledge management effort. Most of what organizations can do involves leverage its "soft power" with employees. Explicit techniques that are authoritarian in nature, or tactics that leave workers with the perception that in down times they can at best expect a culture comparable to that of a police state, only hastens the downward spiral that the organization finds itself in terms of knowledge loss.
Layoffs Send People and Knowledge Packing - ReadWriteWeb
The scale of layoffs over the past few weeks is unprecedented. The impact on these people who have been shown the door and on the companies that have let them go will linger for years to come. Besides the emotional damage that occurs when people are forced out, there is a tangible cost to companies when knowledge and experience walk out the door. Once that knowledge and experience are gone, no amount of TARP money will bring them back. It may be too late for some companies to prevent this now, but putting measures in place will lessen the blow in future.