“…we’re not just winging it.

Rather, we’re endeavoring to make the units of work small enough so that:

Everyone on the team can understand the task being undertaken, and the result we expect it to have.
Regularly and frequently, everyone on the team can reflect on the work done so far, and incorporate lessons learned into the planning for the next steps
Shirky does a good job of conveying the value of the latter point, but I think he fails to understand the importance of the former point.”