Ask HN: what would you build if you could analyze trillions of rows?

With all the Google I/O news, I failed to notice the BigQuery description that reported it was geared towards "analysis over datasets containing trillions of records" ( http://googlecode.blogspot.com/2010/05/bigquery-and-prediction-api-get-more.html ). What interesting things would you do with BigQuery which you could not do before as an independent developer?