If you delete an email from one of your computer devices, does it get deleted from all your devices?
Yes. No. It depends.
Email systems come in two flavors, POP and IMAP. POP stands for “Post Office Protocol; IMAP stands for “Internet Message Access Protocol.” But that doesn’t really tell you much.
What is worth knowing is how their differences affect you.
IMAP systems synchronize with the server and your other devices. When you delete an email from an IMAP account, it automatically deletes from your other devices.
In contrast, POP systems do not synchronize with the server; you need to delete every email from each device manually.
Some email programs give you the choice to be POP or IMAP. Comcast is only POP. If you use a Comcast email address, you have to delete the same email from each device manually.
I am not suggesting that you abandon your Comcast address if you are happy with it. If you retrieve your email from only one computer or if you prefer to delete emails from your various devices manually, you need not change anything. If, however, you wish to have an email address that lets you synchronize with the server (delete once and not see that email again), you can create a email account with a company other than Comcast.
Note: If you pay Comcast to provide you with the cable modem service that comes into your house, you are not obligated to use the Comcast email address you have; changing your email address does not have to mean changing your hi-speed service.