The most efficient and effective method of conveying information to and within a development team is face-to-face conversation.
Now, the first reaction many people have when reading this is to state how much the world has changed since 2001. Now we have Slack! We have social media! We have distributed teams!
It’s true we have those things now. But we also had equivalents to these in 2001, and earlier. We didn’t have Slack back then, but IRC has been around since 1990. In the 90’s it was common to ssh into a remote host and work with developers there. Also, remote teams were common back then, whether it was teams across the country or offshore teams in a remote country. So these concepts aren’t new, and the group that came up with the agile principles was well aware of the concerns.
Face-to-face conversations are always the most effective form of communication. Even teams that are used to working in a distributed fashion find boosts in productivity when a remote team member flies in for a visit.
This should not be taken as an endorsement of bullpen seating so that everyone can be face-to-face with everyone else all the time. Absolutely not. Most of the time developers are programming and don’t need the interruptions. At most, they’re talking with one coding partner.
The main goal here is that when you do have conversations, to prefer face-to-face conversations as much as possible. Ultimately, conversations range in a spectrum from less interactive to more interactive. Communicating via paper printouts is amongst the least interactive, followed by email. Online chats like Slack are good, but can still be rather asynchronous.
Slack is better when you use the call features that share audio, video, and screens. Then it becomes a much more interactive experience. When you can’t have real face-to-face conversations, try to have the next best thing. Remember that live, interactive conversations are more productive.