The text discusses the limitations and potential drawbacks of offering dedicated IP addresses to customers to improve their email delivery. Dedicated IPs are not a guarantee of better delivery, and in some cases, can even harm delivery if they have no reputation or are used for spamming. ISPs prioritize domain reputation over IP reputation, and new IP addresses need time to "warm up" before being trusted by senders. Offering dedicated IPs to all customers is seen as a means of retreating from overall responsibility as an email service provider, placing the burden on the customer instead. In contrast, Postmark takes 100% accountability for its IP addresses and reputation, using shared IP addresses that have a proven history of good sending practices, allowing approved customers to leverage their reputation for better delivery rates. Dedicated IPs may make sense for high-volume senders, but even then, it's not a guarantee of success. Ultimately, the focus should be on proper sending practices and domain reputation rather than relying solely on IP addresses.