Steve Bennett wrote:
.. c) To assist quality control, such as labelling articles that need cleanup etc
It seems rather pointless to me to label 20k pages needing citation. But that's probably not a technical question.
If I do a random walk on en Wikipedia, almost every page seems to have some tag needing something ("This page is in need of <insert your pet peeve here>"). This reminds me of all these "under construction" pages in the earlier days of the web.