Yahoo has presented, through a patent application, the idea of collecting data about people and cars passing by a location to choose what ads to display on a billboard.

The patent application itself is not particularly an issue (other than as an example of a practice, computational idea patents, that is bad in general). Collecting data as envisioned in the application is the issue.

The most important issue is not the use of these data for choosing ads, but collecting the data at all. We need laws to prevent that.