One of the key goals of namespaces in PHP is to avoid collisions between class and function names between different libraries. Using namespaces and the PSR-0/4 standard creates a clean and simple way of sharing code across projects. This is a core part of the Drupal 8 architecture.
This approach has been a large factor in the PHP Renaissance and the huge amount of sharing of code across PHP external libraries.
In this post, I will show how we can leverage external libraries in existing Drupal 7 sites, using similar techniques to how it is being done in Drupal 8.