We've set up a Ning forum for online exchange between a group of people who are in the process of starting their own businesses. We chose Ning because it is super-easy to design and there is a Dutch version. When setting up the forum, you can choose a template, and you can drag and drop the elements you want in your online forum, for instance a blog function, a video upload function etc. You can also choose to make it as easy as possible and to add these elements later (by dragging these elements into your design). I used the video upload function and it didn't work, so I had to find a work around via youtube. I sent an email to report it, and within one hour, I got a reply and it was fixed! I thought this was an amazing service too.
I still can't believe how easy it is to set up these kind of forums as compared to software packages whereby you need a specially skilled webdesigner, webbuilder and webhost to design and build an online forum. On top of the length of the design and build process, there are often the translation problems. It is hard to explain all the features you want, and for the builder it is hard to explain the details of what exactly he is building.
I really wonder what the future of online forum design will look like. Some disadvantages of a free forum for use within an organisation:
1. There are advertisements in the free version (though if you pay something, it will be removed).
2. You may want the look of your forum to match your housestyle.
3. You are stuck with some design features and can not build it entirely according to your own design.
Especially in this phase of experimentation with online discussions, I think it can be a great solution to start with a free and easy-to-set up forum, so that you and the other users have time to find out what features they like/need/desire.