EYE ONDeliverability Monitoring

You can also handle reputation monitoring in-house, using free tools such as Sender Score and SenderBase. These let you know what percentage of your outbound e-mail is being delivered by the ISPs. They aren't definitive sources - Sender Score, for instance, is a service of Return Path, so it "collects data from Return Path ISP customers but only reflects the sender's reputation at those ISPs," [Laura Atkins] explains. Nonetheless, she recommends that even small organizations visit these sites weekly to track their scores. There are several additional steps you should take that don't require any outside tools at all. "Monitor delivery logs to identify if any ISP is blocking outright," Atkins suggests. "This will also show rate limiting, which is often the first sign of a problem at a specific ISP."