I've been working a lot with changing community technology lately, and while I am a firm believer in communities being more than the sum of the technology that brings people together, the tech also matters a great deal. Think of a coffee shop, for example, being replaced by one of those automated coffee machines. While you can still get a cup of coffee, it certainly leaves a different taste in your mouth. Robert Scoble also talks of a similar notion -- of using the right tools for the job, to describe the benefits of podcasting as opposed to say a blog or RSS feed. Why mention any of this?
For anyone looking at technology and community -- pay special attention to your end goals (there are many ways to serve a cup of coffee). Every decision, technical and otherwise, will drastically impact the community in any number of ways.