jamescarr asks random agile question: who should maintain/update the burn-down, customers or developers?
In an ideal world, the developers mark completed and the customers mark accepted/rejected.
This information is then reflected on a stacked burn-down/up chart like in projectcards.
Of course in (my) reality we schedule our iteration and often end up with quadrant I stuff that gets thrown into the mix along the way. So what you see down below is iteration story churn. We're a small team with many projects going at once.
Often the PM serves as the customer proxy and updates the status of tasks reflected in the burn-up/down charts. It is important to note that the PM really does check the product and verify acceptance with the customer.