Me too. From what he did say, I'm pretty sure he's talking about the search terms where user intentions are not clear, based on how frequently that particular query gets revised. In other words,the kind of thing discussed in the 2006 patent we discussed about Query Revision [webmasterworld.com].
In some cases, Google is going a good bit further than a list of refined searches. In fact, I strongly feel that the Position #6 Bug [webmasterworld.com] from last December was part of this "diversity" focus.