One of the next challenges was to figure out how to index the exploding volume of content on the Web.
To solve this, in 2004 @Google invented a new style of data processing (MapReduce) to manage large scale data processing across large clusters of commodity servers.
Google continued to innovate to solve its big data and ML challenges, and created Colossus as the next generation distributed data store, Spanner as a planet scale relational database, ...