Here's a great article from the Federal Times:
Federal agencies are increasingly turning to online technology to hold on to the decades of knowledge that baby boomers will take with them as they retire in coming years. Officials fear that without robust knowledge-retention programs, agencies will lose details of their histories, or forget how certain programs worked and be doomed to repeat past mistakes.
Officials say videos, articles, blogs and other information programs posted on the Internet or intranets are the best way to efficiently pass that information on to younger employees. Knowledge stored online can be accessed at any time and any place — removing the need for employees to travel to hear lectures — and can reach more people than one-on-one mentoring relationships can, they say.