The VIP feature in Mail is useful for prioritizing e-mails from people that you really want to hear from. You start by selecting a contact within Mail on iOS or OS X, and tapping on the “Add to VIP” button. On iOS this will result in a VIP filter, showing only the inbox e-mails that are from VIPs. This is how I envisioned the feature would work before iOS 6 came out.
Mail for OS X is also capable of doing this, but by default, it will simply show you all of the mail you’ve ever received from VIPs. This is not quite as useful to me, since it constantly presents me with a large list of emails, and I want to use VIPs to pare down the amount of email I deal with on a daily basis. But thanks to this tip from Mac OS X Hints, I now know that you can tell Mail on OS X to show just the inbox emails from VIPs – just like iOS does.
This one little change has made the VIP function far more useful to me across all of my devices.