Flattr e-mail connections?
In your Flattr settings you can add an e-mail connection. The text on that setting says: "Content can also be connected to e-mail addresses. Add all e-mail addresses you want to enable flattr for."
Does anyone know what this is about?
There's a support thread open at https://getsatisfaction.com/flattr/topics/e_mail_connections but the answer isn't helpful.
Partner sites can identify users via email addresses. That is the main usage right now. The plan is to enable emails as claim mechanic for flattrs in the future too. So it's good for you that we know your emails.