Yahoo has updated their FAQ and listed out a number of factors they use to determine if a mail message is spam.
- IP Address Reputation
- URL Reputation
- Domain Reputation
- Sender Reputation
- DomainKeys Identified Mail (DKIM) signatures
- DMARC authentication
- Autonomous System Number (ASN) reputation
Autonomous System Number (ASN) is a globally unique number that is assigned to a group of IP networks operated by one or more network operators. Think of an ASN as having a unique number assigned to your neighborhood. Your neighborhood would build a reputation based on the people who live there and what types of emails they send.
Even with positive sending history, users can still mark your messages as spam and that will affect your reputation too. The key is to only send relevant mail to users who have opted-in and want that mail.
Yahoo also includes a number of actions senders can take to improve their delivery:
- Utilize the Yahoo Complaint Feedback Loop to automatically unsubscribe users who have marked your message as spam.
- Use separate IP addresses and mail streams for different type of content.
- Sign with DKIM. DKIM defines who is responsible for sending the message and has reputation tied to the DKIM domain.
- Be consistent with your mailings and watch for throttling.
- Don’t ignore the subject line. Email subject lines are important because users will make a decision based on them and if messages are being deleted without being read, that will hurt your sending reputation.
- Make sure you have PTR records setup for your sending IP addresses.
If your domain is prone to being spoofed, Yahoo does honor your DMARC policy.
h/t to Udeme for the heads up on the updated FAQ page!