To date, most such systems are centrally managed efforts, and that's a problem. The typical setup identifies and catalogs experts in a searchable directory or database that includes descriptions of the experts' knowledge and experience, and sometimes links to samples of their work, such as research reports.
But there are gaping holes in this approach. For starters, big companies tend to be dynamic organizations, in a constant state of flux, and few commit the resources necessary to constantly review and update the credentials of often rapidly changing rolls of experts.
Second, users of these systems need more than a list of who knows what among employees. They also need to gauge the experts' "softer" qualities, such as trustworthiness, communication skills and willingness to help. It isn't easy for a centrally managed database to offer opinions in these areas without crossing delicate political and cultural boundaries.
The answer, we think, is to use social-computing tools.
Activities and interactions that occur in blogs, wikis and social networks naturally provide the cues that are missing from current expertise-search systems. A search engine that mines internal blogs, for example, where workers post updates and field queries about their work, will help searchers judge for themselves who is an expert in a given field. Wiki sites, because they involve collaborative work, will suggest not only how much each contributor knows, but also how eager they are to share that knowledge and how well they work with others.
While I agree with the premise - let us agree that social tools won't just enable adoption - specially if the organization has treated external social networking with a different standard (i.e. by banning access and firewalling them :-)
Adoption of tools will also be slow in organizations where automation is being viewed as something to be suspicious of, or if it entails duplication of work and effort.
The other aspect is - not all experts would like to write about their expertise or might not have the skills needed to cultivate readership or networks.
What does one do then?