It supports blogging, file storage, RSS aggregation, personal profiles, FOAF functionality, media sharing, status exchanger, etc.

Here are some key features of "Elgg":

· Blogging
· Social networking
· File repositories for individuals and communities
· Podcast support
· Full access controls
· Supports tagging
· User profiles
· Full RSS support
· RSS aggregator
· Create communities
· Collaborative community blogs
· Create 'friends' networks
· Import content
· Publish to blog
· Multilingual
· Branding/customization
· OpenID support

Requirements:

· mod_rewrite activated in Apache
· JSON library
· GD library
· Multibyte String support
· PHP 5.2 or higher
· MySQL 5 or higher