That's news to me then. Is there documentation of this somewhere? Search Engine Showdown [searchengineshowdown.com], for instance, says Google doesn't.
Upon trying a few queries, it does seem to work. The typical
(word1 ¦ word2) (word3 ¦ word4)at least appears to work perfectly. How long has this been around for?
site:first. It doesn't check for another
site:, and it separates strings by spaces, which is why the parentheses get moved around.