I have trouble looking at the data (not a bug, more like usability). There are huge sections of the chart without relevant information, just long curved lines. This causes me to scroll horizontaly/verticaly with a little lag until I find interesting text. Maybe something more compact would do the trick without ruining the layout.
Before you go worldwide, you're missing huge sections of the US. Major cities such as Seattle, LA, DC, Austin, and Atlanta all have active early-stage tech funders that don't appear on the map.
It would be nice to just see this as an HTML bulleted list, so users don't need to scroll around. I'm not sure how the spatial relationship is important after you click on a startup hub in the first map -- a multi-level list would be easier to navigate. (My screen resolution is 1400x900 so I'm scrolling in all directions after a click).