It's an interactive map that shows the locations of companies, universities, labs, etc. that are working in nanotechnology in the U.S. The metros of the "NanoMetro map" are areas with 15 or more sites, and they show up as red circles when you're zoomed out. If you zoom in to a specific region, you can check out the different sites, color-coded by sector (electronics, energy and environmental applications, imaging and microscopy, medicine and health...).
You could use the map to find potential partners in your region, but I found it interesting to use to get a sense of the different sectors represented in a region. When I searched Washington, DC, where I live, all the dots were purple (academic and government research) or white (organizations). But when I searched Boston, MA, where I used to live, the dots were mostly a mix of purple, blue (materials), and green (medicine and health).
Check out the NanoMetro map here. 
Here's the DC map:
And here's the Boston map: