Cost vs Benefits of Wikiprojects
Just signing the previous entry: Jorge Stolfi (working mostly in the English Wikipedia).
Actually, I think that this evaluation is overly optimistic. The danger of Wikiprojects is not so much that they siphon off effort which otherwise would have been a contribution towards the goal of the overall project. It is not necessarily the case that the time spend on bureacratic activities would otherwise have been spent on article quality (after all every user decides for himself how much time he spends on what activity) or that if the time were to be spent on articles it would lead to an improvement in quality.
The danger of Wikiprojects is that they may form independent communities, each with their own distinctive community values (bias, etc), and that they may work at cross-purposes from what the overall project is trying to achieve. The focus should be outwards, on reality, on actual knowledge and on how to make it accessable. Once there is a community the risk is that the focus turns inwards, playing the community game; then the overall project loses out. - Brya 06:46, 22 January 2010 (UTC)
This definitely occurs, with the projects forming strong communities, lobbying acceptance of policies, going all together to deletion reviews etc. But I expect that with the increase of the project mass these effects become less pronounced, whereas the availability of expert to comment/help creating/help improving articles increases.