My new media idea of the week

I've been thinking about new applications that would let you "see" breaking news, facilitated by Twitter. I am interested in developing an application that lets you choose your location and see a live visualization of a text cloud formed of everyone's real-time tweets and text messages in the area. As with a map, you could zoom in or out on these aggregated tweet clouds to see them at various magnifications. People could see tweet frequency for a specified location displayed in various visualizations, e.g. stock market performance charts. Users could set thresholds (as one enters a preferred price on a web site that offers airfare-watching) so that when those norms are exceeded by a certain amount, the software notifies them automatically (by sending an email/text message/call).

I suppose if you could filter by location you could just as easily filter the messages by content and search on key words, as this blogger suggests here: http://bolindigital.com/time-location-emotion

But would people really allow this use of their content and see it as an invasion of their privacy? Or would there be a way to make it cool to opt in to add your own reporting to the mix? People could opt in to include their updates in the meta-tweet cloud -- Call it The Instant Reporter or something snappy, make everyone a contributor.