To gain a better understanding of Creative Commons Licensing in action and how individuals use and work on open access content I took a look at the Wikipedia pages on the American Civil War and Abraham Lincoln. The edits that I noticed on these pages included grammatical changes and phrasing changes as well as citation and reference changes and additions. The Civil War page seems to have many different contributors that make small changes here and there while the Abraham Lincoln page seems to have main editors that work through the details of the page during certain periods of time.
In terms of the Creative Commons Licensing of our own site, we will probably use something very open. We are creating a site to provide not only information about the subject of the letters but also to digitize and make accessible the collection. The intent is that people will read, share, us and download the content from our site. We are making a public and usable exhibit for people to be able to use as they please, as long as the copyright on the materials themselves allows for access.