Anyone who has ever used a combination of email, phone, meetings and other media to communicate in a small group has experienced at least one moment where they've thought, "this would be going much better if we were having this conversation using X".

While the choice of X is often driven by personal preference and comfort levels (as someone who spent a few years being a sysadmin, my X is email), I believe there are several scales along which the various media can be measured. The resulting values (which are very much dependent on the context of the medium's use) can be used to choose a medium depending on the goals of the group or the individual initiating the conversation.

The three scales that are usually most relevant for me (I'm primarily concerned with enabling action and reflection) are:

Degree of Synchrony

Does the medium provide for synchronous or asynchronous responses. This depends not so much on the quickness with which a participant responds but rather whether the communication to which a response will eventually be made is stored for review. On the phone you can wait for a long time to make a response, but eventually you may forget what the other person said. This isn't the case with email.

Desired result of communication

Action versus Reflection. Should the participants be inspired to perform some action or to continue thinking at the end of the conversation? How does the medium encourage one or the other?

Degree of Ambiguity

How clearly does the medium transmit already clear concepts? How effectively does it indicate there is doubt? What degree of doubt or noise does the medium inject into the conversational space?

These scales can be used to make three axes defining a three dimensional space. Each medium fits somewhere in the space. Each scale impacts the others.

• synchronous ... asynchronous
• action ... reflection
• ambiguity ... clarity

Neither end of any scale is bad. Each is good in some ways: effectively expressing doubt is a way of showing that there is room for reflection or a need for more information. However, using a medium that introduces or enhances ambiguity in a setting where quick action is required is a bad idea.

Wikis, Weblogs and Email are all asynchronous media (the content is stored for later use) but they work more effectively in different areas. Email, because it is pushed to the reader, is often more effective at causing action. RSS feeds from wikis and weblogs could inspire action, but thus far there is not much of a tradition of use along these lines. They are more effective at reflection, especially wikis, which allow in place refactoring of content.

IRC, phone calls and face to face meetings are synchronous. IRC can introduce a great deal of noise where processes of use have not emerged. It can be a place for causing action, but leadership is required. It is often good for dipping into a shared pool of understanding for a bit of reflection. An unexpected phone call can inspire action while a pre-arranged conference call or face to face meeting is only effective with the help of processes and structures that facilitate the use and construction of information artifacts that will live on after the call.

Where would you map the various media? What dimension matters most to you? Someone could make a graph.