An enterprise class database, PostgreSQL boasts lots of modern features, that makes organization of data of your website more advanced

Formal description:

PostgreSQL - is a free object-relational database management system (ORDBMS) and is ranked as the most developed of the open source databases in the world.

In other words:

PostgreSQL - reliable and performance driven database which allows you to store many types of data.

What is it used for?

It makes sense to use PostgreSQL for data storage when your website includes a large expandable database which is extensively in use. PostgreSQL can also be utilized when increased security and reliability are required.