The big new feature in Mountain Lion’s Mail app isn’t really a Mail feature at all: Notification Center will now flash up an alert for every new e-mail you receive. But this can get old fast, especially if you get a lot of e-mail. Thankfully, you can tweak these setting to be finer-grained, and a lot more useful. And you can do this by making your friends VIPs.
Mountain Lion Mail Adds VIPs, Notification Control

