Intranets are private computer networks within an organization that utilize standard network technologies like Ethernet and TCP/IP. They provide benefits like improved communication, collaboration, web publishing for internal documents, and business management tools. While intranets use the same protocols as the internet, they are firewalled for security. Content management involves roles like content creators, editors, publishers and administrators who manage versions and permissions. Open-source intranet tools like Drupal and Joomla allow customization of intranet design and content through modular frameworks.