I don't have time to do this site justice but ECOresearch Network's Election 2004 site is extraordinary. Using analysis of a wide number of sites, thousands of online documents etc the system tracks interest in and keywords associated with the candidates in the US presidential race. Especially cool is that non-US sources are included in the analysis and you can track changes in metrics over time. Very nice.
The site describes it as:
This project of the ECOresearch Network automatically provides a weekly snapshot of international media coverage. The results reflect media attention and attitude towards the US presidential candidates. Keywords grouped by political party and geographic region summarize the issues associated with each candidate.