Well, I asked for a wiki almost three years ago, but it is finally here in official capacity. Thanks! In the few weeks of its existence, we have already seen great progress in documenting many development issues that were previously undocumented or hidden in strange places. I have started to keep my personal notes and todo items, which were previously spread around various files and pieces of papers, under User:Petere.
I have been observing the wikification in the Debian project for a few years now. I expect that in the near future, all of the contents relevant to developers will have migrated from the main web site to the wiki.