MPP is an enterprise-grade email filtering solution designed specifically for Xserve email servers. It has the most advanced antispam engine available and provides virus protection, content filtering, email archiving, attachment stripping, attachment blocking and more. MPP also has a web-based system for spam quarantine and archive review, and is available as a VMWare virtual appliance, supported under VMWare Fusion.
Mia for Gmail (was Notifier Pro for Gmail) is a desktop Gmail client which sits politely in your menu bar.
