How do some others tell when we open an e-mail message from them?

Question

Maybe to do this people generally pay for a service. Is there a way to stop spammers from finding out when we open one of their messages?

Answer 1

Spammers usually use a small (1x1 pixel) image hosted on their website or something like that. Block by not automatically downloading images in mails.

Corporate users often have the option of a 'read receipt' or 'delivery receipt'. Block by setting Outlook to never send read receipts.

Answer 2

Set your outlook express settings to never mark as read, so even when you click on the e-mail it will never mark it as a read mail and will not send a read reciept, that way you can look at the e-mail and decide what to do with it without actualy opening it, and therefore it will never send a read reciept.