in reply to Detecting an email address
If you mean getting a confirmation that the mail was read, then it can be done, if I take your question literally, then no.
But the ways to achieve that have nothing to do with Perl, and it's an evil thing to want. In either case, if I knew you were doing this, I'd go offline before opening your mail - if I did so at all.
It is none of your business if folks in your userbase choose not to disclose their real email address to you.
Makeshifts last the longest.
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