They want to know what you have to say. Once they know more and trust you, they can buy what you sell. Permission must be granted . Buying names and addresses and then sending direct mail to these prospects is not permission. It's spamming, and guerrillas know spamming litters the marketing scene and is usually ignored.
Permission is selfish .
Your prospects will grant you permission only if they clearly see there's something in it for them. You've got about three seconds to tell them what that something is. Permission can be revoked . As easily as permission is granted, it can be withdrawn. On the other hand, it can also intensify over time.