Just like Information Architecture, Knowledge Management can be a divisive term. I have had a surprisingly large number of KM practitioners tell me they avoid the term "KM", making up any number of variants or trendy euphemisms to replace it, because of its bad connotation within the business world.
Granted, there have been some spectacular KM failures in the past. In the 80's and 90's KM was often associated with large, clunky programs that were expensive, took forever to implement, and showed very little benefit.
However, as a term, I have yet to find anything as succinct and to the point as "knowledge management". What does it mean? KM is, quite simply, the conscious management and nurturing of the information a corporation knows or needs to know to achieve its business goals.
The reason the definition of KM gets into trouble is because people then try to nail down what a corporation needs to know or specific approaches for how that knowledge is to be managed. So conversations about KM waver between abstract catch phrases -- like the right information to the right people at the right time or from data to information to knowledge -- to strictures about exactly what information should be captured and how.
The fact is that what information a corporation needs to know varies from corporation to corporation and from moment to moment. Influences on what information is needed include what information they already have, how they do business, who does what, how much they trust each other, etc...
Another very strong influence is what information is already being managed within the corporation. Many companies already have an employee directory (usually managed by HR or IT). So this may not be information that needs any additional attention. But the larger the corporation gets, the more they focus on organizational structure as a classification system -- both on the intranet and in the employee directory (where manager is more important than current role, say). The larger and more diverse the corporation, the harder it is to find out what is actually being done within the company. What projects exist, what was done in the past, who is working on them and what is their status? These are questions that can be vitally important but equally difficult to answer.
So, from a pragmatic standpoint, KM within any specific company often ends up being responsible for filling in the gaps between other existing programs, such as HR, the Program Management Office, IT Management, Quality & Standards, etc.
One last comment about defining KM: note that I bounded the scope of the definition to what a corporation needs to know to achieve its business goals. The boundaries of what can be known are limitless. But the resources to manage that knowledge are not. Even the knowledge within a small company is fall beyond the capacity of any reasonable program to control or influence. Does everyone really need to know where Doreen keeps her stapler? No. But it may be critically important that everyone in the group she manages knows where she posts the task schedule for the week. Whether information is knowledge or noise is contextual. Determining the relative value of information in different situations is a key starting point for -- and determining factor in the success of -- any KM initiative.