Each time a WHOIS lookup is performed, depending on the context of its data it may be requested from either the registrar or the registry. We will cover a few of the differences and how this may impact changes that you make on your domains in the control panel.
If you have been following the ICANN article referencing the .com / .net TLDs to move to Thick WHOIS, in time the .com / .net gTLD's will become a thick WHOIS lookup rather than a thin WHOIS lookup and fall in line with other gTLD's. You may see the timeline here and the updated document at ICANN here.
What is a Thin WHOIS lookup?
A thin WHOIS lookup provides limited technical data from the registry which would include identifying the sponsoring registrar, the status of the domain, along with the creation and expiration dates. The remaining data, that being the contact details, are stored directly at the holding registrar(OpenSRS). Examples of this would be .COM and .NET, which soon will be moving to thick WHOIS as per the articles above at ICANN.
What is a Thick WHOIS lookup?
A thick WHOIS lookup contains all the technical data with the registry, as such administrative and technical, owner contact details. In addition, the sponsoring registrar and registration status. With data handled directly at the registry level and not the registrar, there are limitations and restrictions to how the "domain lock" works, while making changes to contact details.
Examples of thick WHOIS lookups would be, .INFO, .BIZ, .NAME.
How does this affect me?
Making changes to your domain, domain locking/unlocking, and contact changes are all affected by thick and thin WHOIS lookups. You may see our support article regarding "Lock or unlock a domain" which outlines how the details are handled.
When making contact changes for TLDs that have thin WHOIS data, the domain lock does not prevent contact changes as the contact data is held directly with OpenSRS(The sponsoring Registrar).
While making contact changes to TLDs that have thick WHOIS data, the domain lock prevents contact changes from being changed, the data is held in the registry instead of the sponsoring registrar.