I have a mail server. I use QMail, SpamAssasin, SPF. My mail server is NOT an open relay, never was used to send spam, it isn’t listed in any RBL list and so on. Nevertheless every time I send an email through my e-mail server to an Yahoo! account it gets to the Bulk folder.
I was wondering what are the rules that Yahoo! uses to mark a message as spam and send it to the Bulk folder. I read all I could get my hands on and still no luck in fighting this odd Yahoo! behaviour.
All multiple sends are called bulk. You need to get your contacts in address books to avoid this.