With great collaboration comes much communication. When we build a software product, a lot of information changes hands. To get things done rapidly, it needs to change hands both at a fast pace and accurately.

Any discussion, answering and asking questions, work coordination, and so, on will get resolved more quickly when it happens face-to-face. 

Each of us has a combination of predominantly three different learning styles—auditory: learning via the spoken word, visual: learning by seeing, kinesthetic: learning by doing. When communicating with a group, it's good if we can engage all three learning styles, as this will increase the learning bandwidth, plus ensure we include people who might prefer one style over another.

So to keep knowledge transfer rapid, it is easiest to do with an interactive, in-person face-to-face interactive conversation, preferably with a whiteboard or some other form of visual communication so that we engage multiple senses at once. 

To maintain a high level of knowledge transfer requires a fairly small group. When people around him were advocating for increasing communication, Amazon CEO Jeff Bezos' response was to say increasing communication is terrible and he introduced the two pizza rule. This meant that a team should be no bigger than can be fed by two pizzas. Anything over that size and information will start to get lost and the group will become nonproductive. High-bandwidth communication in small group trumps sitting in nonproductive meetings all day.

For example, compare the difference between a small birthday gatherings to a wedding. At the birthday, we invite a few close friends and family. The small group makes it possible to hold meaningful conversations with all of our guests, leaving us with the sense that we really shared the moment. 

When we get married, it's a once in a lifetime event, we invite many guests. It's challenging for us to get around to all of them, our conversations are only fleeting, and the wedding can end with us feeling that we haven't had the opportunity to share our special day with everyone who came.

Next, we illustrate why communication gets so tricky once we move beyond a certain number of people.