This is interesting. The owner of a Ferris wheel named the "London Eye" has a system in mind which will allow the Ferris wheel to chart how people feel about the Summer Olympics.

A computer will place all local tweets about the Summer Olympics into one of two categories, "positive" or "negative." The percent of positive tweets will influence the lights on the Ferris wheel, allowing people who see the wheel to visually gauge how Britain feels about the event.
Source