One of the most consistent headaches elearning and knowledge management programs encounter is an inability to reach the full potential of an initiative or new tool (blogs, wikis, collaborative spaces).
The problem can almost be reduced to a formula/rule (principle of actual use):
Each tool/initiative achieves actual use in relation to potential, based on: the nature of tool, the environment of use, and the people using the tool/initiative.
Nature of tool - How complicated is it? How different is it from how work is being done now? Complexity is proportional to adoption and intended task.
People - Is the targeted user willing to adopt and explore new processes? Will it save time? Will it result in increased productivity? Will it help them better do their work? Will it improve their sense of competence (or will it reduce competence due to frustrations)?
Environment of use - Does the tool/initiative solve real problems for the end user? (or only management)? Do people have to alter their work habits to use the tool? Can they do their job without it (if they can, most won't adopt it)?