Yeah, one of my future plans is to setup an API so real-time data could be entered into the site. I also want to make changes so that point data can be added in (i.e. lat/lon) so that it's easy to do real time tracking of things - e.g. whales, birds, ships, ... etc. The lat/lon changes would also allow things like earthquakes, fires, floods, world's tallest buildings over time, 7 wonders of the world ... etc to also be mapped.
Keep in mind that some stuff (such as 7 wonders of the world) and other somewhat stationary data is better added in OpenStreetMap - but for the other cases, you're tool could be a good solution. I'm looking forward to updates to it!
Thanks again for that feedback. Yeah, with stuff like the 7 wonders of the world I think you're right in that it's well covered in other ways. I guess I was thinking more along the lines of the ancient wonders of the world. I think events showing when they existed, and how long for, would add an extra dimension to people's understanding. For example, I don't know if they all existed at the same time or not (which of course a simple Google search would reveal), or how many years ago the first wonder was constructed, or how many years apart they were. I'll try it out at some point and see what people's reaction is to it.
Maps is not free - as you mentioned, you pay with data.
However, there are FOSS and privacy respecting alternatives, most are based upon OpenStreetMap - wikipedia style map of the world. Some data is still lacking, but at least you yourself can fix it if you want to.
Perhaps you could also support real-time sensor data? Services as Luftdaten.info would love to have these visualizations.