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.
There is a very important difference between the two, though. The "under
construction" pages are an excuse for a lack of content. They were
supposed to show to the visitor that someone's working on it and that
it'll be ready "Soon™". The Wikipedia tags, however, are an invitation
to participate, i.e. a request to someone else. They are a productivity
tool, and they are meant to help improve the content, not the visitor
frequency.
Timwi