Update: We have now gone for Vanilla forum which is really nice. PHP4 but has a really nice interface, next step Framework integration!
This is more for notes to myself for now – that I installed bbPress (by the same developers as WordPress that this blog runs on) and Phorum 5. To see if they are any good / worth using at work (eg will they integrate well with other web tools/the Zend/AEA Framework, how well are they written and documented, whats the licensing etc).
This integrates quite nicely with WordPress (uses the same users) would be good if it could use more of the WordPress installation stuff (eg templating). Also has a nice Poll plugin (although code for this looks a bit hacky).
Cons: PHP4 based, Doesn’t look very mature from its version number, GPL license might cause issues when integrating.
Phorum 5: http://sucrose.cronky.net/phorum/
Particularly interested in this one as it looks good / feature rich but it is also BSD licensed making it more flexible to customise and incorporate into other frameworks without having to re-release an Open Source version.
Cons: Again PHP 4 based.
Silverstripe Forum Module (need to install on dev box)
The other thing to consider is whether a dedicated tool like one of the above offers compelling advantages over the Silverstripe Forum module (although the Forum module is a bit alpha in our experience so far – but then it is at v0.1.2!)
Some benefits of the SS module include PHP5 / MVC implementation, that we are already using SS for CMS anyway…