Composer provides you with a new and simple way to describe and install a project's dependencies. Finally using third-party libraries in PHP projects is as easy it should be. PHP development is shifting from building large monolithic code monsters to assembling projects from small single-purpose easily-reusable libraries. Composer was inspired by concepts from Node.js npm, Ruby's Bundler and other package management systems.

Composer is quickly becoming the leading method of managing projects. Projects including Symfony, Zend Framework, Doctrine, phpBB and the Facebook PHP SDK are all adopting Composer. The Packagist statistics demonstrate its fast adoption rate.

In this core conversation, Nils Adermann (creator of Composer), will show how Composer can not only help Drupal, but also your next projects. We'll answer your questions about making effective use of Composer and how Drupal core could benefit from it.

References:

Composer Download & Documentation:
http://getcomposer.org
Composer Package Repository:
http://packagist.org
Drush wrapper:
http://drupal.org/project/composer
Initial Drupal 8 patch:
http://drupal.org/node/1424924