The most effective wiki improvement we can make

[Minh Ha Duong]

is perhaps this one:

The capabilities of mediawiki build-in search engine are very limited. Too 
often, we don't find what we are looking for. We need to extend this facility 
with something more powerful. See options at 
http://www.mediawiki.org/wiki/Category:Search_extensions

Especially:
http://www.mediawiki.org/wiki/Extension:GoogleSiteSearch

Minh