Just ran across ChronoZoom this AM, which immediately reminded me of Prezi in the way things zoom around. It does look pretty cool, but so far appears to only contain content produced by the beta participants. While this makes sense as a beta, I really hope they open it up to contributions from a wider community.
ChronoZoom is an open source community project dedicated to visualizing the history of everything to bridge the gap between the humanities and sciences using the story of Big History to easily understand all this information. This project has been funded and supported by Microsoft Research Connections in collaboration with University California at Berkeley and Moscow State University.
I also don't like that you can't link to a specific piece of content, but a really good illustration of the timeline feature is if you take a peek at the World War II Tour:
You can view use the project on your iPad, which is cool. Here's a nice video introduction: