How does WHOIS information differ across different top-level domains (TLDs)?

WHOIS information can differ significantly across different top-level domains (TLDs) due to variations in policies, regulations, and management practices by registries and registrars. Here are the primary ways WHOIS information can differ:

1. **Policy Differences**:
   - **ICANN-Managed TLDs**: For generic TLDs (gTLDs) like .com, .net, and .org, ICANN has established specific WHOIS requirements that registrars must follow. These policies dictate the type of information that must be collected and made publicly available.
   - **Country Code TLDs (ccTLDs)**: Each country code TLD (like .uk, .de, .jp) is managed by a national registry that sets its own WHOIS policies. These can vary widely, with some ccTLDs requiring extensive public information and others offering more privacy protections.

2. **Data Elements**:
   - **gTLDs**: Typically, WHOIS records for gTLDs include information such as the registrant's name, address, email, phone number, as well as technical and administrative contact details.
   - **ccTLDs**: The amount of information required and displayed can vary greatly. Some ccTLDs, like .us, require detailed public information similar to gTLDs, while others, like .ca (Canada), have stricter privacy rules that limit the public availability of registrant information.

3. **Privacy and Proxy Services**:
   - **gTLDs**: ICANN allows the use of privacy and proxy services, which registrants can use to shield their personal information. These services list the proxy service's contact details instead of the registrant's information.
   - **ccTLDs**: The use of privacy services varies. Some ccTLD registries permit them, while others require full disclosure of registrant information. For example, .au (Australia) has restrictions on the use of privacy services.

4. **Regulatory Compliance**:
   - **GDPR Impact**: The General Data Protection Regulation (GDPR) in the European Union has had a significant impact on WHOIS data for TLDs that serve EU residents. Many registrars now redact personal information from public WHOIS records to comply with GDPR, displaying only minimal data like the registrant's country and anonymized contact information.
   - **Local Laws**: ccTLD registries must comply with their respective national data protection laws, which can result in different levels of data availability and privacy.

5. **Format and Access**:
   - **Standardization**: WHOIS data for gTLDs tends to follow a standardized format prescribed by ICANN, making it relatively uniform and easy to access.
   - **Variation**: ccTLDs may use different formats and systems for displaying WHOIS data. Some may offer web-based lookup tools, while others provide command-line access or require email queries. The user experience and the extent of data available can vary accordingly.

6. **Accuracy Requirements**:
   - **Enforcement Levels**: The level of enforcement for accurate WHOIS information can vary. ICANN requires gTLD registrars to verify and maintain accurate data, but enforcement can be inconsistent. Some ccTLD registries might have stricter or more lenient enforcement policies based on their governance structures.

In summary, WHOIS information varies across TLDs due to differences in policy requirements, privacy laws, data elements collected, the use of privacy services, regulatory compliance, and the mechanisms for data access. While gTLDs generally follow ICANN's guidelines, ccTLDs are governed by their own national or regional policies, leading to a diverse range of practices regarding WHOIS data.