I always enjoyed interactive stories--especially on historical topics.
There are still just a few spots where I think they could have done better (when viewing documents, some don't seem to be links to a detail view) but it is impressive.
What I'm wondering is whether a web app like this one will stand the test of time when new versions of web browsers, javascript libraries will replace the old. Will we still be able to enjoy this story in 10-15 years from now?