Sometimes we get clients with a big subscribers base, for instance, 4 000 000 contacts. They have been collecting it for years, but have not sent any email and want to start doing it now.
You can't expect effectiveness from such a base: over these past couple of years a part of these addresses has become invalid, others have already forgotten they subscribed. Sending emails to these addresses is risky, because it may lead to many undelivered emails, spam complaints, unsubscriptions, it may result in reputation decrease, email clients will always mark your emails as spam.
In these cases you should work with the base very carefully: to clean up all the invalid addresses (for example, with the help of Xverify
), then try to reconfirm the left ones in small portions - to send them an invitation once again and ask to reconfirm their interest. After that a great part of the base will be lost, but some part of the contacts will remain as your subscribers, and you will minimize the risk of getting into spam.
The best tactics is to start working with the contacts as soon as they appear in your base.