Another public Google project that I have played a significant part in is the Google Knowledge Graph.

There are many benefits to indexing human knowledge in structured form (as opposed to indexing strings for keyword search). The features we are adding to search that make use of this data are reason enough to develop the Knowledge Graph because they are very useful to searchers today. However, I think we are only at 1 percent of what is possible with having a structured knowledge repository and that is the exciting part to me.