Aside from replying to an e-mail, what do you do when you have multiple projects to manage by e-mail? There is a great online task management tool at producteev.com that turns Gmail e-mails into tasks and then syncs with outlook so that you can track projects and tasks, deadlines and your calendar. Using this type of online tool will really support you to stay on top of e-mails that are actually parts of projects.
If you need a simpler version of online task support, and don’t use Gmail as your primary work e-mail account, or dislike Outlook, there are easier e-mail management centers out there you can try for free. I looked at EmailCenterPro.com as a possible tool to recommend to you. If you are really overwhelmed by all the things to do in your e-mail Inbox, there is a definite advantage to trying out a service that supports you to create a better project management system so that you can track multiple ongoing projects.
If you feel limited by what your business e-mail account has to offer you as far as project management features, take 10 minutes right now to look online for a better solution.