Mail.app is a good application but the problem faced by the users is that the application gets slow if you are a regular E-Mail user and your inbox is flooded with GB’s of mails.
MailTags is a plug-in for Mail.app and adds a new panel in the main window and some additional features in the menu. The application allows you to annotate messages with Meta information such as tags, text note etc.
You can also create iCal Todo entries without leaving Mail.app which eventually speeds up your work.
The application is recommended for all users who have an average number of E-Mails and want that system to work fast.
Via: oreilly
