From The Art Of Community by O'Reilly (http://www.artofcommunityonline.org) by Jono Bacon
Choosing Your Mediums of Communication
Your community has oodles of communication channels to choose from, each with qualities that make sense in different scenarios and to different people. The goal is to match the right medium to your community and to understand the pros and cons of that medium to help the pros bubble to the surface and keep the cons well away from the kitchen.
Picking an appropriate medium is largely about understanding your contributors and their workflow. Each type of contributor will have different preferences.
Another key consideration when building effective communication channels is keeping discussion focused. This is a two-part process in avoiding communication fetishism and also keeping all your eyeballs in one place.
Communication fetishism is particularly prevalent in online and technical communities and points to the problem of new communities wanting to provide every possible communication channel under the sun. They set up mailing lists, forums, IRC channels, Second Life worlds, and more. This is the wrong thing to do. You should instead identify the key roles and personalities in your project and choose mediums that make the most sense to those roles.
When you set up a new community, you want to generate discussion quickly. You want to initiate the discussion but encourage and inspire others to participate and get involved. If you have a forum with too many subforums, you will fragment the discussion: you will get many tiny bits of discussion across the subforums, and little consistency. Keep the discussion in just a few places, and conversation will flow.
Mailing lists are an excellent medium for discussion. They are low bandwidth, a familiar interface (email), and fairly accessible, and conversation is delivered directly to your email client. The delivery of the conversation reduces the chance of new contributors forgetting about your community: each time they check their email, they are reminded that your community exists, and they may actually read the messages and respond.
Forums are a very popular, low-barrier-to-entry medium. They manifest in the form of websites that allow you to create an identity and have a discussion using that identity.
Forums have exploded in popularity in recent years, and some huge forums have developed across the Internet.
Forums are a popular choice among less-technical users.
IRC is a real-time chat medium that has become increasingly popular for communities. There are IRC providers all over the world, and many IRC networks cater to specific purposes. As an example, the Freenode network (irc.freenode.net) is specifically aimed at providing IRC channels and conversation for open source projects. Although an entirely open and accessible medium, IRC is still very much populated by technology-related channels.
The value of IRC is in real-time discussion, and there are many benefits:
With the continued growth of blogs as not only a personal publishing medium but also a community publishing medium, you may need to write articles, stories, and features about your community.
Magazine articles/web articles
Your community may get the opportunity to be featured in a magazine or website, and you will need to be able to present your thoughts well.
Your community will produce documents, guides, specifications, help, and more, and these should be clearly written and easy to read.