I made the mistake in my last post of taking internal communication for granted and did not make mention of the means a team may take to synchronously communicate to one another online. I have long been a member of the converted, spending lots of my online time on irc in development related channels (mostly public channels on freenode) and have even used irc as a major communication mechanism for the last year long project I was involved. I thought it was a wonderful tool for the job - especially given the amount of remote development we were conducting.
However, when explaining my usage of irc for professional and development purposes to non irc denizens, I could never find the appropriate analogy for it. I can thank Neal Ford for giving me one now. During Ford's leading keynote at TheServerSide Java Symposium '09, he talked about developer productivity and how cube farms are detrimental to developer productivity. I couldn't agree more. Of course, every developer would love to have their own office space, but this is not possible given limited office size. So instead he explained the concept of a "war room", or an open room full of nothing but developers where the only conversation revolves around the project - it is pretty popular over in the Agile world, it seems.
So what piece of technology can encompass that same concept for communication? It is not IM and email, which are so riddled with non-development noise that it is hard or impossible to filter and can easily lead to distraction for the concentrating developer who is short on time and has precious mental cycles to spare. The best solution would be irc. It is synchronous, channel based, filterable, and most clients support nick highlighting so that only messages directed to you are highlighted - easily allowing a conversation to take place within a conversation. I'd take it one step further than the virtual water cooler analogy that was given. I dare say that irc is the quintessential online war room for developers. I would also ammend my previous list of things needed to bootstrap a development team and place irc as a must have.