There is a seach facility located in a block on the left hand side of every MoodleDocs page. You can enter your search text and then click either 'Go' or 'Search'.
If you select Go, or press Enter, it first looks for an article with exactly the given string as its title, and if one is found immediately goes to the indicated article. If Go fails to find an article, it then automatically executes Search.
Search is a full-text search for the given words listing Articles with titles that match first, then articles with matches in the main body of the text.
Note that this search method currently ignores words of three letters or less.
Searching MoodleDocs and Moodle.org forums with Google
The search box at the top right of the Moodle.org homepage will search both the contents of the Moodle.org forums and the MoodleDocs wiki at the same time. This search is powered by Google which has some unique search features but this means the results are not updated immediately when the content changes.
Firefox search plugin
You can seach MoodleDocs from the search box in the Firefox browser by downloading a search plugin from here
Mac OS X widget
A dashboard widget for Mac OS X that searches MoodleDocs wiki is also available. See this forum post.
Searching MoodleDocs from your Moodle site
You can search this site from your own moodle site by using the Search MoodleDocs Block