This is a complex topic: how to manage the subscription of an already stored email address?
Let me to illustrate some situations:
- the address is already confirmed
- the address is still in confirmation wait
- the address is bounced
- the address is unsubscribed
To start, consider the bounced status: if that email address has been marked as bounced, it means the mailbox cannot be reached (for some reason). If someone try to subscribe with that email address, how we should treat it?
Actually Newsletter plugin shows a configurable error message which invites the subscriber to contact the administrator.
Probably you think: where’s the problem? If, as it should be, the double opt-in is used, simple send out the confirmation email for all the cases except for the already confirmed status.
Where is the problem? The problem is to protect against situations where “fake” subscriptions force the Newsletter plugin to send out email which can be considered unwanted and marked as spam – lowering the trustfulness of that domain.
For example if firstname.lastname@example.org is unsubscribe and any of you try a subscription, I’ll receive a confirmation request email, which is something I probably don’t want. But if I unsubscribed and then I want re-subscribe (it may happens), getting an error message is not the best way to recover old subscriptions.
What’s you opinion?