I am looking for a application to install in my server having the following features:'
- A global dashboard
- Newsleter (Optional)
- Q/A (Optional)
I already found a application: TWiki, but looking for a better alternative.
OpenAtrium covers the wiki and article publishing part by default. You'll need to manually enable the forum part—it comes with the forum components that Drupal comes with, but there seems to be some minor incompatibility with OA (mainly just that each group can't be given its own default forum); though I've seen other OA installations with working group-specific forums, so maybe I just need to tinker with it a little more.
I'm not sure what kind of quiz functionality you need, but that probably isn't hard to add.
OA also comes with a customizable dashboard; again I don't know what specifically you need in it, but it should be pretty easy to add anything that you need.
It sounds like you're looking for something like the Atlassian package of applications.