Are you treating dealing with your email as one task on your to-do list?
Do you get frustrated at how many hours a day you spend on it?
Is your measure of success dealing with all of it? Do you then chastise yourself for never succeeding?
Email is a medium for communication.
The fact that something comes to you by email doesn’t make it more (or less) important that something that comes to you by some other means.
Your inbox contains all different kinds of communications. Their priority varies based on the content and possibly based on the sender.
The fact that you have not dealt with all the e-mail that comes in from an e-mail discussion list is not a failure on your part. In fact it might be a sign that you are prioritizing your work well.
The task is to sort your email
Some of what’s in your inbox is important. Going into your inbox to determine what’s in there and what needs doing with it is an important task. But it should take you minutes.
Some of that can be automated. You can create rules in your e-mail program to automatically move student e-mail to a specific folder, for example.
Create to-do list items for specific things
Or schedule time to deal with all the communication related to a specific area of your work.
For example, decide how much time per week you are willing to devote to student communication and how you will divide that time between in-person office hours, dealing with e-mail, etc. Schedule time to do those things. Let your students know how quickly they can expect a response to an e-mail. (And feel free to delete any e-mail the answer to which can be found in your syllabus without responding.) Set up an autoresponder to acknowledge receipt and remind the sender of your target response time.
If you are on a committee and materials for the next meeting arrive by e-mail, have your e-mail program sort those into a separate folder and schedule a meeting with yourself before the committee meeting to go through all the material you received.
You can do the same with chapter drafts from your graduate students. There is no need to read them as soon as they arrive as long as you read them before the meeting or within a time frame agreed with the student. (A 1-week turnaround is probably reasonable.)
Keep in mind that you are not a cardiac surgeon. No one dies if you leave your work lying on your desk (real or virtual) for days.
Also, not everything requires a response.
Charlie Gilkey has created a tool to help you triage your e-mail. Email Triage costs $10 (USD) a small price to pay for a saner way to deal with e-mail. (I don’t get any money for referring you there. It’s just a good product.)