There is no evidence that spammers collect email addresses from business cards or from promotional material.
If email addresses are published as part of a promotional campaign, it is worthwhile using a different email address created specifically for each campaign. If a spammer gains control over a third-party computer through Trojan software and the user of such a computer responds to such a promotional campaign, there is a possibility that the Trojan software will pass the promotional email address back to the spammer's central database. By changing email addresses for each campaign, the accounts can be suspended once the campaign has finished.
