Merge branch 'conformance-challenges-working-draft2' into conformance…

…-challenges-working-draft.

Merging Shawn Lauriat's content addition into our Working Draft so we
can review all proposed additions and edits in one file."

conformance-challenges/index.html

@@ -137,6 +137,8 @@ <h2>Challenge #2: Large, complex, and dynamic websites are always “under const
 		<section>
 				<h2>Challenge #3: 3rd party content</h2>
 				<p>Very large, highly dynamic web sites generally aggregate content provided by multiple entities. Many of these are third parties with the ability to add content directly to the website – including potentially every website visitor. While the website can provide guidance on how to post content so that it meets WCAG Guidelines and Success Criteria, it is ultimately up to those third parties to understand and correctly implement that guidance.  And as noted above, even with automated checking prior to accepting the post, too many Guidelines and Success Criteria expect human validation involvement.</p>
+				<p>Copyright and other things that restrict the ability to modify or impose requirements on third party data can also make full page conformance impossible to assure. For instance: articles that allow reposting
+				   but without modification due to copyright restrictions.</p>
 		</section>
 		<section>
 				<h2>Challenge #4: Non-Web Information and Communications Technologies </h2>