What is IP reputation today vs 10 years ago?

A decade ago, IP reputation was everything. Mailbox providers judged senders primarily by which server sent the message. Dedicated IP addresses were considered essential for serious email programs, and warming a new IP was the critical first step in any deliverability strategy.

Today, domain reputation has become the dominant signal at major providers like Gmail. This shift happened because senders constantly change infrastructure, and spammers exploited the ability to abandon burned IPs for fresh ones.

IP reputation still matters, particularly at Microsoft and enterprise filters that rely on IP-based blocklists. But for Gmail, which processes over 30% of global email, your domain's track record carries far more weight than your server address.

The industry moved from inspecting the ship to inspecting the flag. You can repaint the hull, but the flag reveals who you really are.