One less technical way I've seen this handled is with a footer something like: ---- If your friend or colleague has forwarded this to you and you would l

One less technical way I've seen this handled is with a footer something like: ---- If your friend or colleague has forwarded this to you and you would like to SUBSCRIBE to our mailing list, click here. If you are the subscriber (THEIR@EMAIL.ADDRESS) and would like to unsubscribe, click here. ---- The unsubscribe page also has large text with the e-mail address that has been unsubscribed and an undo button, and the unsubscribed account is sent one more e-mail (after a short period) confirming the unsubscription with a link to re-subscribe if they want to. It doesn't prevent malicious unsubscription, but help to prevent or reverse accidental unsubscriptions of the type in the article. It also "works" in all email clients.