In a topic there is a link
/index.php?module=forums&type=user&func=emailtopic&topic=x
This feature is only available to logged-in users, as it should be to protect from spam bots.
I think it needs a couple of additional features.
Include the username of the referring user in the email sent. Like "user x sends you this link" Including possible their "Real Name" if it is available since usernames are often obscure.
These emails should be logged in the database with senders username and IP in case of abuse complaints.
Possibility of using captcha to further prevent abuse.
Configurable sending limits on how many a user can send per hour.
In a topic there is a link /index.php?module=forums&type=user&func=emailtopic&topic=x
This feature is only available to logged-in users, as it should be to protect from spam bots.
I think it needs a couple of additional features.