Collaboration means working together to get something done. At a minimum, I think your intranet should facilitate the following three types of collaboration:

Instant Collaboration

Goal: Share ideas and get immediate feedback
Offline equivalent: Face-to-face meetings & phone calls
Online solutions: MSN Messenger, Google Talk, WebEx, etc.

Instant collaboration tools include instant messaging and desktop screen-sharing. Your intranet should provide links or downloads for these tools and instructions on how to use them. Advanced integration could include an indicator beside names in the employee directory to show who’s online.

Project Collaboration

Goal: Plan and execute a project
Offline equivalent: Status meetings & war boards
Online solutions: BaseCamp, Central Desktop, eProject, etc.

Project collaboration tools usually include a shared calendar, to-do lists, message boards and a file repository. Your intranet should link to your project collaboration tool and include suggestions on how to use it effectively. Advanced integration could include a personalized to-do list on the intranet home page.

Mass Collaboration

Goal: Ongoing sharing, learning and connecting with teammates
Offline equivalent: Team off-sites, workshops, conferences
Online solutions: Confluence, SocialText, ThoughtFarmer, etc.

Mass collaboration solutions make it easy to create, share, and find content. They include wikis, blogs, and social bookmarking. The best ones leverage the network effect to aggregate individual contributions in ways that create value for the entire organization. Your intranet shouldn’t be integrated with a mass collaboration solution. It should be a mass collaboration solution.

The intranet team should pursue ownership of all types of online collaboration and integrate them into a single portal. The future for intranets is mass collaboration.

Further reading:

Collaboration Types: Part One, Two and Three

List of mass collaboration applications