Last sunday, Luc de Louw published more statistics on the TYPO3 mailing lists. We can now peek into some charts about the mail queue.
The charts give us an impression about how many mails were defered in the postfix queue. You can compare this value with the total amount of incoming/active/delivered mails. This information does neither reveal the reason for queuing or the duration mails spent in the queue. But it gives us a first impression about the server (postfix) load.