The ultimate search engine would understand exactly what you mean and give back exactly what you want.
Thank God he also admits that we're not there yet (although Google no doubt works hard toward this goal).
Natural language understanding (NLU) is so much more than a word for word "decoding" of the linguistic meaning. Understanding "exactly what [one] mean[s]" requires full-blown NLU (rather than simply NLP) techniques and approaches. Linguistic and pragmatic context for instance figure big in NLU. And so are some "usability" aspects of the query for instance the intentions of the querent, assumptions and underlying inferences.
The search engines of the future will allow for a query to actually organize matching knowledge they mine from the internet instead of simply match against some web text. So when you plug in a query like "what is the cost of buying a house in Costa Rica in 2009?", you will expect something more specific and on-point than a list of "relevant" documents.
