IssueLab has implemented 1) a CC license chooser to the upload process, 2) license marks for the site itself and for CC licensed resources, 3) a subset of the CC REL specification, and 4) search for CC-licensed resources.
IssueLab has implemented a CC license chooser so that users can select a CC license to apply to their work during the upload process:
On the same page as the CC license chooser, Issuelab has included an informational sidebar about CC licensing:
IssueLab has a CC license mark on the footer of the site indicating that content on the site is licensed under CC BY:
The CC license mark also appears on pages for resources that have been CC licensed by uploaders
For example, see this page of a whitepaper uploaded by Creative Commons under a CC BY license:
For example, see this code on the home page:
<a rel="license" href="http://creativecommons.org/licenses/by-sa/3.0/us/"><img alt="Creative Commons License" style="border-width:0" src="http://i.creativecommons.org/l/by-sa/3.0/us/80x15.png" /></a> Except where otherwise noted, all content on this website is licensed under a <a rel="license" href="http://creativecommons.org/licenses/by-sa/3.0/us/">Creative Commons Attribution-Share Alike 3.0 United States License</a>.
They have also implemented rel="license" on pages for content uploaded to the site and CC licensed by users.
For example, see the source of the page for this article:
<a rel="license" href="http://creativecommons.org/licenses/by/3.0/"><img alt="Creative Commons License" style="border-width:0" src="http://i.creativecommons.org/l/by/3.0/88x31.png"/></a><br/>This work is licensed under a <a rel="license" href="http://creativecommons.org/licenses/by/3.0/">Creative Commons Attribution 3.0 Unported License</a>.
You are able to access more structured data about the resources curated by IssueLab using their OAI-PMH access point.
IssueLab lets you search for CC licensed resources. Simply go to the advanced search page and at the bottom select the checkbox saying "Check if you'd like only Creative Commons licensed works.":