What happens to spam delivered the Junk folder by the Anti-Spam Quarantine feature?
Currently, it simply fills up the Junk folder until you delete it. We recommend you delete everything over one month old in that folder, as it is very unlikely that any messages that old would be legitimate message incorrectly marked as spam that you have missed. In the future, there may be a feature to automatically purge old messages from this folder, but this feature hasn’t been created yet.