Do inbox providers share email deliverability data with each other?

Marketer from Email Geeks suggests that it would be shocking to know if ISPs are sharing data with each other, as that is exactly the bad practice they punish when brands use third-party data, indicating it is highly unlikely.

Email marketer from Reddit mentions that while explicit deliverability data is not shared, ISPs use similar spam filtering technologies and share threat intelligence, leading to correlated outcomes. If one ISP identifies a sender as malicious, others may independently reach the same conclusion.

Email marketer from MailChannels explains that several email providers subscribe to common blocklists managed by third-party organizations. If an IP address or domain is listed on one of these blocklists, it can be blocked by multiple providers.

Email marketer from Litmus Community comments that industry groups and conferences facilitate informal data sharing and collaboration among email providers. This helps them to coordinate efforts against emerging threats and improve overall email security.

Email marketer from Email on Acid shares that while providers don't share specific delivery metrics for individual senders, they collaborate on identifying and mitigating widespread threats like botnets and phishing campaigns through joint industry efforts and data sharing platforms.

Email marketer from Mailjet details that while email providers don't explicitly share user-specific deliverability data directly, they do share aggregate data and cooperate on threat intelligence to combat spam and phishing. They use feedback loops and standards like DMARC to improve overall email ecosystem security.

Email marketer from Sender Score indicates that companies like Sender Score aggregate data from various sources, including feedback loops, complaints, and sending behavior, to provide a reputation score. This score can influence deliverability across multiple ISPs.

Marketer from Email Geeks notes that Yahoo used to handle the backend for AT&T's email which might explain why better Yahoo practices are also seeing a lift at sbcglobal and att.net.

Email marketer from Validity responds that email providers use feedback loops (FBLs) to share information about spam complaints. This enables senders to remove users who mark their messages as spam, improving their reputation across multiple providers.

Email marketer from Return Path explains that reputation data is shared indirectly through blacklists and whitelists, which are used by multiple providers. If a sender is blacklisted by one provider, other providers may also block their messages.

Email marketer from StackExchange answers that email providers often use shared reputation feeds or blacklists, such as Spamhaus or Proofpoint, to identify and filter spam. This means that a negative reputation assigned by one provider can affect deliverability across multiple providers.

Expert from Word to the Wise explains that while the idea of direct data sharing between ISPs is a myth, they do share *threat* data such as botnets or other malicious actors, and also indirectly share through Feedback Loops and shared blacklists.

Expert from Email Geeks explains that ISPs are very clear that "just because X likes your mail doesn’t mean we do" and that there are privacy implications to sharing user data with 3rd parties.

Expert from Email Geeks shares that ISPs do share data, but it’s threat data (malicious actors and botnets) more than delivery data.

Expert from Spam Resource explains that ISPs use feedback loops (FBLs), and while they don't directly share all data, FBLs provide senders with data on user complaints, which indirectly informs other ISPs' filtering decisions. Reputation data is a major factor which impacts your mailings across multiple ISP's

Documentation from IETF explains Abuse Reporting Format (ARF) which is used by email providers to report spam and other abuse. This information is shared, enabling other providers to take action against malicious senders.

Documentation from Google Workspace Admin Help explains that Gmail uses various signals including user reports, sender reputation, and content analysis to filter spam. Google shares aggregated, anonymized threat data with other providers through industry consortiums to improve overall spam detection capabilities across the internet.

Documentation from Microsoft explains that they participate in data sharing initiatives, such as the Microsoft Active Protections Program (MAPP), to share threat intelligence with trusted partners and security vendors. While it primarily deals with security threats, this collaboration can indirectly impact deliverability.

Documentation from RFC Editor explains that Internet Service Providers (ISPs) and other network operators routinely share information about network threats. This collaboration enhances the ability of each entity to protect its own network and users.