What are the Buzz Charts?

The Buzz Charts are derived from a number of sources, including commit activity, mentions on webpages, and short-term news and discussion. Each source is weighted based on overall importance and influence on "buzz", then added together to produce the buzz rating.

Of course, the ratings were never intended as a scientific measurement - rather as an interesting and fun way to record the popularity of an entity against another, and how this changes over time.