A link in the footer (down by the copyrights, timestamp,
and disclaimers) labeled "Cite this
article|page|whatever" be very useful. It make the life
easier for students using wikis as sources for their
papers. Ease of citation is a good way to ensure that
wikis actually get cited, which will generate more traffic,
which will generate better content, and so on.
The way I envision this feature working is that when a
user clicks the "Cite this article" link, a small pop-up
window would be generated, containing a proper citation
for the current revision of the article in a number of
popular formats (e.g., APA, MLA, MHRA).