...below those sitelinks (a kind of a onebox, or you may call it an extension to the Sitelinks feature). I cant reproduce this yet, so it might be a test... try a search for nasa, arsenal fc, mit and others to check if the site search box shows for you.

More about Sitelinks can be found at Googles help entry. Also, see Googles site operator, which lets you search on just a single domain in the normal search box.

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