Lately, my associates and I have been doing quite a bit of social network visualization research for clients, typically using raw social data and comprehensive, fee-based custom tools. While these are great for deep analysis and strategic planning, sometimes a simple free tool can do the trick if all you are looking for is quick high-level insights. I would like to point out two such tools today, both of which rely on the Twitter API.
Tips, Insights, and Occasional Rants On Digital Culture, Social (Behaviour Change) Marketing, and the Modern Social Media Landscape