MediaWiki supports full text search. The limitations of this feature is that it indexes only words longer than 3 characters. If you want to search for shorter words (1 to 3 characters) then a known workaround is to use Google's sitesearch feature. Enter your search items in the form and it will automatically search within Pop!_Planet.
Of course, you can do the same manually by appending
site:pop-planet.info to Google searches:
your search items site:pop-planet.info
This works fine, but it is not live. Google is indexing Pop!_Planet every 1 to 3 days.