The display of maps and data within an interactive framework is becoming more prevalent online. I'm thinking beyond merely the ability to pan/zoom/control layers, but more along the lines of displaying spatial and non-spatial data, together, in a unique format (e.g. animated charts).

For example, this website goes beyond mapping and presents spatial data as a learning and exploration tool with graphical data summaries, text summaries, animations, etc.

What are some good examples of well-designed interactive maps using modern technologies, and what are the advantages/disadvantages of these tools? What technologies should be avoided?