Network Knowledge Activity - Ancestry.com

After I had posted my example of an activity, I visited my Ancestry account to get some information.  As I got distracted and cleared a few hints, it occurred to me that this was a huge knowledge network.  Think about how the user works within the Ancestry site.
After setting up an account (membership), you name your family tree (or trees) and you start entering the data you know.  This usually involves collection of data from the family to start.  The data you have is entered into the web site in an organized fashion (curation) that provides data points where the data you have input can them link to other data within the archives.  Those data point come up as hints which you can add to your data or reject as irrelevant.  This repeats the the collection/curation cycle in a loop as your family tree grows.
Some of the hints will link to family trees that other users have built in the database.  You can choose to not link to those trees, but if you do, then your information on the data point has now shared with others linked to that person in your tree.  When you review their data, you can see the source of their data to judge its validity and compare it to your own.  In effect, you are brokering your own and their data when you accept to link you data to each of these others.  It becomes a joint data project, where, as you add data to the shared data point, the other users see that new data and hints they can add.  When data is questionable or confusing, you can contact the other users through the web site to negotiate what data points are trustworthy enough to save.
In my personal tree, I have traced my family back to Bridgewater, MA, when the land for the town was purchased from the local Indians.  And my family married Mayflower passengers, making me a son of the Mayflower.  The negotiation process became important as well when there are eight men named John within four generations of my family.