We are building a content based portal. Along with the content, we want to provide some collaborative tools- i.e. chat, forums, online directories etc
We are hoping to leverage open-source software for this, as this isn't really a differentiator and will hopefully be faster/cheaper. I am looking at light integration between the content and these (common login, ability to easily reference content in chat/ forums etc) and am flexible on features being offered- as long as the broad functionality is achieved.
We have hosted on MS Azure- what should our considerations be towards identifying the right product?
Joomla! is one option. You want to ensure that the majority or all of the tools you are looking for are openly available no your chosen platform. It is hard to make a solid recommendation without much detail on the content, but you can check it out here:
http://www.joomla.org/about-joomla.html
It is free and open source, site says
Joomla is used all over the world to power Web sites of all shapes and sizes. For example:
Corporate Web sites or portals Corporate intranets and extranets
Disclaimer: Have never used Joomla