
The eXo Platform 3.0
Here's a look at the eXo high level architecture again:

eXo Platform 3.0
Yes, they have been showing the eXo Collaboration and eXo Knowledge services in the model for awhile now. But even though eXo Platform 3.0 isn't here quite yet, the services that make it up are slowly being released.
First we saw eXo Social, then eXo Web Content Management. Today we have a closer look at the two latest services released. Again, all modules support the GateIn Portal built by eXo in partnership with RedHat, and run on Tomcat 3.0 and GateIn 6.0 out of the box. And as per usual, they are free to download under the open source Affero Gnu Public License (AGPL).
eXo Collaboration
So what makes up the collaboration module? It may not be what you think. It's interesting to see eXo identify tools for collaboration whereas most vendors mix collaboration and social capabilities into a single bucket of features.
Here what we get are tools that allow users to work together including a web-based email client, address book, chat and calendaring. The tools are built on open standards, supporting standards such as vCal, iCal, SMTP, POP3, IMAP, vCard, XMPP.

eXo Email Client
All include a rich Ajax-enabled interface that provides easy drag and drop capabilities. And they are integrated together, so you can access the Calendar and Address book directly within your email.
Here's a look at eXo Collaboration (@5min):
Getting Started with eXo Collaboration from eXo on Vimeo.
eXo Knowledge
eXo Knowledge supplies tools that let you find the experts and/or the answers you need to do your job. Included in the service are:
- Forums: Create content using a rich text editor, run polls, rate messages, create private messages, set up user profiles, notifications and more.
- Answers: Submit questions and answers, rate answers, ask for more details, moderate and manage.
- FAQs: When you get a question/answer combo that you think is good to share, publish it to the FAQ page.

eXo Knowledge 2.0
A New API Service
Along with eXo Collaboration 2.0 and eXo Knowledge 2.0, a new API service is now out for Preview. Unlike eXo Social which supports OpenSocial, there no APIs available to supply developers, so eXo has built new ones.
Today they offer the API to the developer community for Peer Review to make sure the service is usable and works as expected. This API is used by all eXo services, so developers can build apps in Java or Groovy and then expose RESTful services to integrate with back-end systems.
Although everything is available now to download and use, commercial support won't come until the Q4 release of eXo Platform 3.0.