It is possible to perform search on Wikipedia, which includes history along with current page content.It would be especially good to search in deleted articles or deleted passages of articles.(If no, is it possible to do so with at least Mediawiki engine?)
Is it possible to search Wikipedia including deleted text?
mediawiki;wikipedia
There is a Wikipedia Revision History Search here;http://wikipedia.ramselehof.de/wikiblame.php?project=wikipedia&lang=enHope this helps.