William forwarded me a link to this awesome site: Cooperative Research History Commons. The site is a cooperative approach to history and presents data in timelines (here is the list of events in the Nixon Administration and Watergate timeline). I like this vertical approach to wiki data as it has the potential to focus both expertise and data structures, making the data more valuable in a number of dimensions.
The website is a tool for open-content participatory journalism. It allows people to investigate important issues by providing a space where people can collaborate on the documentation of past and current events, as well as the entities associated with those events. The website can be used to investigate topics at the local, regional, or global level. The data is displayed on the website in the form of dynamic timelines and entity profiles, and is exportable into XML so it can be shared with others for non-commercial purposes.
I'm sure we are only moments away from seeing a slick visualization of this site.
(It would have been interesting to see the interaction between an objective project like this and historical memories such as those which the BBC's The Time When project aggregated - it is now, sadly, closed).