Opion::

"discovers and forecasts emerging patterns and trends by identifying and ranking opinion leaders in digital public discussions and correlating their behavior with real-world events. When change is increasingly driven by chaotic public discussions, Opion spots important events at their earliest stages, then tracks and predicts their spread and impact. We find the people with the most contagious ideas, while preserving each individual's privacy."

Their CEO says they could apply their product to all markets. Right now they have a financial application that tracks stocks, and another one on entertainment that relates buzz and box office sales (and movie studios seem to like the pseudo-viral stuff).

08/15/04 update: this company was acquired by PlanetFeedback two years ago, itself a division of Intelliseek, a company increasingly involved in tracking weblog content.