Supposedly, some ISPs recycle dead accounts as spam traps. http://docs.briteverify.com/spamtraps/ http://docs.briteverify.com/spamtraps/ Now, keep in mind the

Supposedly, some ISPs recycle dead accounts as spam traps. http://docs.briteverify.com/spamtraps/ http://docs.briteverify.com/spamtraps/ Now, keep in mind the source of that information sells mailing list cleaning solutions, and it may be "email marketer" superstition, I don't know.