This key element - the ubiquitous data store - is not your classical relational database aka RDBMS. Instead, it's a new kind of database (architecture), viz. NoSQL or the non-relational database.
The following presentation is an excruciatingly detailed, but very good look into the innards of the NoSQL Database architecture, and also helps to understand how this compares to RDBMS.
Thanks to Lorenzo Alberton for putting together this wonderful presentation.
See also, 'Building Scalable Web Applications: The Non-relational Way!', which provides a glimpse into the new, emerging trend of non-relational aka NoSQL databases.
See also, 'Building Scalable Web Applications: The Non-relational Way!', which provides a glimpse into the new, emerging trend of non-relational aka NoSQL databases.