One problem with using other forum (or quiz, etc) software, is user confusion due to interface switching. If you've had to support 1000s of users using several different software applications, you'll know what I mean.
IMO, this gets to the core idea; why use an LMS at all? Why not use a forum from one place, a quiz tool from another, a content management tool from another vendor/project, yet another project for chat, etc. etc. and loosely couple them all together for authentication?
Sounds like a great idea from the point of view of a person who likes to learn numerous different interfaces. Often the majority of users of an LMS are students and faculty who often do
not want to have learn different interfaces to get their work done (and who frequently tell me that they already have too many different interfaces to learn). There has been interesting work by Carl Berger, and others, looking at early adopters (willing to spend time learning different software applications, forgiving of bugs and mistakes) vs. the early majority, who tend more to want a single, simple system that is 'easy to use' and 'does just what I need it to do, and not more'.
From an overall perspective, each user will have to spend time learning what buttons to push to get their desired result in each of the different interfaces they are asked to use, as this time is multiplied over thousands or tens of thousands of users, IMO it may be more practical in the long run to build new features into Moodle rather than expect users (and support staff) to spend time learning different UI's for each feature.
In our recent evaluations of different LMS systems with faculty, the fact that Jforum (
java phpBB clone) was so different from the rest of Sakai was counted as a strong
negative by the faculty in the evaluation group (this example may be helpful as a reason JForum was integrated into Sakai was to provide features not offered by Sakai's forum module...on the other hand JForum doesn't integrate with Sakai's gradebook, is not backed up nor restored by the course archiving tool, etc. It's loosely integrated, which lets jforum development continue on it's own pace and schedule (in theory), but not tightly integrated (which would likely require common development agreements and compromises between Sakai and jforum or a fork of jforum for sakai--in which case you start to work your way back to the original problem
.
It may also be interesting to note that for just about every Moodle tool there are individual open source and/or commercial tools (quiz engines, contend delivery, gradebooks, etc.) that could be used instead. In many cases these individual tools were available since the late 90s. I think a big reason LMS systems (Blackboard, WebCT, Moodle) have been more popular with end users (faculty, students) than loosely coupled collections of individual projects is that for these users the benefits of a general system with a unified user interface outweighs the immediate benefits offered by using collections of non-integrated projects.
