Read the Drupal README if you want to know what it is. Otherwise I’ll assume you understand the concepts of a FLOSS modular CMS/web-application generator in a LAMP environment.
Aspects of drupal of relevance to the IP Community Commission
- Aggregator: syndicating content
- Archive: view content by date
- Blog: a blog for every user
- Comment: allow comments on content
- Taxonomy: categories and classification schemes