Drupal is open source software maintained and developed by a community of 630,000+ users and developers. It's distributed under the terms of the GNU General Public License (or "GPL"), which means anyone is free to download it and share it with others. This open development model means that people are constantly working to make sure Drupal is a cutting-edge platform that supports the latest technologies that the Web has to offer. The Drupal project's principles encourage modularity, standards, collaboration, ease-of-use, and more.
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