The colors reflect the CKAN rating: datasets with high average rating are green, those with low average are red. The intensity of the color signifies the number of received ratings: a strong color indicates many ratings, while a near-white color indicates few ratings, and unrated datasets are white.
If you click on any node, you will be taken to the package details page at CKAN. Nodes with more than 5,000,000 triples have short names next to them. Hover over any node to get its full name.
This visualization is based on the same underlying data as the LOD Cloud, by using the Comprehensive Knowledge Archive Network (CKAN) API to pull all the packages in the the lodcloud group. More about how this graph was generated can be found in the lod-graph project at GitHub. Please submit Comments/questions as issues on Github, or in conversation on the public-lod discussion list.