Sender Reputation Data (SRD) is a unique email feedback system operated by Microsoft. The goal of the SRD program is to derive a better picture of a sender's reputation by using feedback from trusted voters, rather than using complaint rates, which can be misleading. To get feedback, Microsoft re-sends emails that had already been sent to subscribers on their panel of SRD voters within the previous 24 hours. The message comes from Microsoft Spam Fighters and the sender's original subject line with: [Microsoft Spam Fighters] Junk or Not?.
How SRD works
In the SRD email body, subscribers vote on whether they think the email is junk or not junk. A junk vote is seen as negative feedback and a not junk vote is seen as positive. SRD emails are re-sent for all mailers, not just Certified senders.
Why SRD is important
SRD feedback is more reliable than feedback derived from complaints because senders can lower complaints by sending more volume. Senders cannot artificially lower SRD rates.
Why SRD rates are statistically significant
Microsoft indicates that each SRD vote is typically representative of 50,000 to 100,000 Microsoft users. This means 5 negative votes represents at least 250,000 recipients.
