For those interested in what's dropping in the fall with iOS7, it seems that there will be a slight change in the way Wikipedia search is integrated in to Siri.
Currently, you would need to explicitly use the name to search Wikipedia results alone or primarily ("Search Wikipedia for surfing" or "Wikipedia surfing"). It seems that they'll be using more natural language in iOS7, with phrases such as ("Tell me about surfing"), and also using something a lot more like the information snippets in Google Now or Quick View.
Here's a screenshot from today's keynote, which to me seems thin on attribution...
