Throwing work at people or throwing people at work

Shuffling people around, moving them from project to project, pushing them into multitasking is one of those management errors we seem to be making all the time. The scary thing is that still a substantial part of the management population is convinced that this is the most optimal way to use scarce resources ("human resources", people are treated the way we treat machines, as if they were "mechanical", swapping in and out). We have tasks to do, well let's throw the right people at it, done.
In the agile mantra, we believe that throwing work at people - instead of throwing people at work - is a much more effective way of working. We learned the fundamental importance of team dynamics, the fact that it takes time to build and that the fastest way to make it vanish is to the frequently change the team composition by swapping in and out people.
The recipe is to define projects with a broad enough goal/mission (expected throughput time at least a couple of months), assign a dedicated team to it with people full time assigned to it (exceptions are allowed, but stick to exceptions). When new tasks/stories pop up, push them to the most appropriate team (task closest to the project goal/mission), and let it be handled as another requirement/story on their backlog. Don't micro manage, but ride the waves of team dynamics.