Karl has offered this post explaining the difference between a task board and a Kanban board.
He draws attention to the common task board focus of tasks to do this iteration. No WIP limit, only tasks currently in development.
This differentiator becomes less apparent when we look at how teams develop their use of task boards. Personally one of my prime reasons for using a white board over an electronic tool is to open up the possibility of the team changing the layout.
It is common for teams to apply the mantra, don’t start something new if you can support an existing activity. In addition to, always ensure that you are working on the highest priority story to which you can contribute. While this is not a fixed WIP limit it does reduce the work in progress in terms of both tasks and stories.
It is also quite normal for a team to choose to show upcoming stories where early analysis is due in preparation for a sprint. Add to this a column for acceptance testing, again not unusual, and we begin to see similarities.
I really appreciate the contribution that the Kanban community have made to our collective body of knowledge. However, it may be beneficial for them to more openly recognise the broad overlap in values between Kanban practitioners and the rest of us agile folks.