Quotas, quotas and more quotas…
Apple Mail does an amazing job of managing SPAM, integrating with iPhoto and Address Book and helping users stay organized. Just as keeping your files organized on your Mac can help you keep your hard-drive from becoming too full, keeping your inbox organized can help you keep your mail server as empty as possible. One neat trick I recently discovered in Apple Mail lets you quickly check how much of your mail server space is free! Simply open Apple Mail, select an inbox and hit Command-I.