Summary
Email marketers, experts, and technical documentation provide insights into the variety of old and unusual email domains found in databases. These range from domains of defunct providers (e.g., 'prodigy.net', 'juno.com'), country-specific domains, and a surprising prevalence of 'aol.com' addresses, to domains of long-defunct universities, numerical domains, and those using IP addresses. Historical factors, such as older registration practices, less standardized DNS configurations, inactive TLDs, and outdated syntax standards, contribute to these unusual finds. Pre-standard email addresses, as well as domains of acquired/renamed companies, also persist. Finding instances of WebTV remind us of how quickly technology evolves.
Key findings
- Defunct and Legacy Domains: Domains from defunct ISPs, long-gone university or organizations and companies that were acquired or renamed persist in databases.
- Geographic Specificity: Country-specific domains and those designed for specific services (like WebTV) are identifiable.
- Persistence of AOL: A surprisingly large number of users still actively use AOL email addresses.
- Unconventional Formats: Numerical, IP address-based, and pre-'@' symbol email addresses can still be found.
- Historical Registration & Standards: Older registration practices, less-standardized DNS, inactive TLDs, and outdated syntax standards contribute to unusual domain names and formats.
Key considerations
- Data Validation: Implement robust data validation to identify and handle obsolete or non-standard email addresses.
- Compatibility: Ensure system compatibility with older formats when dealing with historical data.
- Deliverability: Assess the deliverability of email addresses with unusual domains; some may be more prone to bounce or be flagged as spam.
- Security Implications: Assess any potential security implications related to interacting with outdated or non-standard email formats.
- Domain Reputation: Consider the reputation of older or less common domains when sending emails, as they may affect deliverability.
What email marketers say
10 marketer opinions
Email marketers and community members have observed various old and unusual email domains in databases. These include domains from defunct internet providers like 'prodigy.net', 'compuserve.com', 'juno.com', and 'netzero.net', as well as country-specific domains rarely seen globally and a surprising number of 'aol.com' addresses. Additionally, unusual finds encompass defunct university domains, numerical domains, IP address domains, and email addresses with pre-'@' symbol formats.
Key opinions
- Defunct Providers: Domains from defunct internet service providers persist in older databases.
- Geographic Specificity: Country-specific domains may appear unexpectedly in global databases.
- AOL Longevity: A significant number of users still maintain 'aol.com' email addresses.
- Unconventional Formats: Numerical domains, IP address domains and pre-@ symbol formats are occassionally discovered.
- Academic Institutions: Domains that were only for long defunct university email addresses can be found.
Key considerations
- Data Accuracy: Ensure data cleaning processes account for outdated or unusual domain formats to maintain database accuracy.
- Historical Context: Recognize that unusual domains may reflect historical internet practices and user behavior.
- Domain Validity: Verify the validity and deliverability of email addresses with unusual domains before sending communications.
Marketer view
Email marketer from Email Geeks shares how they recently mapped about 800k domains to Google Workspace and O365 and shares an example of an odd domain they found.
10 Aug 2023 - Email Geeks
Marketer view
Email marketer from Email Marketing Forum explains that they still see a surprising number of 'aol.com' email addresses in their database, indicating that some users have maintained these accounts for a very long time.
19 Mar 2022 - Email Marketing Forum
What the experts say
3 expert opinions
Experts in email and spam have noted that older databases may contain email addresses with domains that are rarely used now but remain active due to company acquisitions or name changes. Additionally, some email addresses predate modern standardization, utilizing characters or formats now considered invalid. One expert recalled creating content for WebTV, showcasing how technology and related online behaviors evolve, impacting email address formats over time.
Key opinions
- Legacy Domains: Domains from acquired or renamed companies may persist despite low usage.
- Pre-Standard Formats: Email addresses predating modern standards use now-invalid characters/formats.
- Technological Evolution: Changes in technology, like the rise and fall of WebTV, impact email address formats.
Key considerations
- Data Validation: Implement robust validation to identify and handle obsolete or non-standard addresses.
- Domain Analysis: Regularly analyze domain activity to identify potentially outdated domains.
- Historical Awareness: Acknowledge that legacy addresses may represent long-term customers or important historical data.
Expert view
Expert from Email Geeks remembers making a version of a website just for webtv and then getting thank you emails from webtv users. Mentions Microsoft's idea to merge webtv with a dvr and call it "UltimateTV".
29 Apr 2022 - Email Geeks
Expert view
Expert from Spam Resource explains that some domains, while still technically active, are rarely used for new email addresses but persist in older databases, such as those from companies that have been acquired or changed names. This can lead to some being seen as unusual.
23 Aug 2023 - Spam Resource
What the documentation says
5 technical articles
Technical documentation highlights several reasons for finding old or unusual email domains in databases. Older registration practices, less standardized DNS configurations, and the existence of TLDs that are no longer active or have fallen out of favor all contribute to this phenomenon. Furthermore, older syntax standards allowed for email address formats that are now considered invalid, such as those with unescaped spaces or unusual characters. The under-representation of Internationalized Domain Names (IDNs) in older data also makes their presence in legacy databases relatively unusual.
Key findings
- Historical Registration: Older domain registration practices produced less standardized domain names.
- Non-Standard DNS: Less standardized DNS configurations contributed to unusual domain names.
- Inactive TLDs: Some Top Level Domains (TLDs) are no longer active or have fallen out of use.
- Outdated Syntax: Older email syntax standards permitted formats now considered invalid.
- IDN Under-representation: Internationalized Domain Names (IDNs) were less common in older data.
Key considerations
- Data Validation: Implement robust validation to identify and handle obsolete or non-standard domain formats.
- Compatibility: Ensure compatibility with older email address formats when processing historical data.
- Security: Assess the security implications of interacting with email addresses using outdated syntax or defunct TLDs.
Technical article
Documentation from MXToolbox provides insight into the kind of DNS configurations used that were less standardized. This resulted in more unusual or less standardized domain names compared to modern conventions, leading to now-uncommon domain extensions.
19 May 2023 - MXToolbox
Technical article
Documentation from ICANN notes that older databases may contain a higher proportion of email addresses without Internationalized Domain Names (IDNs), making the presence of IDNs relatively 'unusual' when encountered in legacy data.
3 Nov 2024 - ICANN
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