Only Accessibility-Supported Ways of Using Technologies: Only accessibility-supported ways of using technologies are relied upon to satisfy the success criteria.
Any information or functionality that is provided in a way that is not accessibility supported is also available in a way that is accessibility supported. Non-Interference: If technologies are used in a way that is not accessibility supported, or if they are used in a non-conforming way, then they do not block the ability of users to access the rest of the page.
Conformance to a standard means that you meet or satisfy the 'requirements' of the standard.
This list is not exhaustive, and is limited to notable, well-known sites.
The Alexa website rankings are from various time periods.
(Conformance is not possible at a particular level if any page in the process does not conform at that level or better.) An online store has a series of pages that are used to select and purchase products.
All pages in the series from start to finish (checkout) conform in order for any page that is part of the process to conform.
Although content may satisfy all Success Criteria, the content may not always be usable by people with a wide variety of disabilities.
Therefore, usability testing is recommended, in addition to the required functional testing.
Statements about "part of a page conforming" cannot be made.
Sometimes, supplemental information may be available from another page for information on a page.
The note points out that authors are encouraged to go beyond conformance to a particular level and to complete, and report if they desire, any progress toward higher levels of conformance.
See also Understanding Conforming Alternate Versions which includes techniques for providing Conforming Alternate Versions.
Although conformance can only be achieved at the stated levels, authors are encouraged to report (in their claim) any progress toward meeting success criteria from all levels beyond the achieved level of conformance.