WHOIS data element chart
Here's a [PDF] chart of data elements found in registrar and registry WHOIS services.
The chart (prepared for WHOIS Task Force 2's purposes) ignores .name (which is special), and TLD-specific data elements like eligibility related elements in the sponsored/restricted TLDs, and trademark information in .info and .pro. Also ignored: name server names v. name server IP addresses, opaque database keys, contacts' "organization" fields.
