Facebook held one of its hackathons earlier this month, in which the company's engineers stay up all night working on development and hopefully, come up with site improvements or features that its users will appreciate.

AllFacebook points us to one of the results of the November 5 hackathon, a nifty visualization of Facebook user activity (see video below). Using a 3D model of Earth, the app shows the data Facebook receives, including density by location (note how brightly lit the U.S. is at all times) as well as routes of Facebook user interactions.

It's a cool-looking app that's curious for a couple of reasons, one being its use of Java. Facebook killed its official Java client back in May, leaving developers to put together their own version of a Facebook API for Java developers.

The other curiosity relates to the amount of activity the map is showing, versus what it would like if it were released to users. The data visualization is certainly cool, and comments on the video post include requests for the ability for users to have the app themselves. However, without the full dataset from Facebook, there really wouldn't be much to look at. Most users simply don't have enough friends to generate an interesting map.

Moreover, to implement the tool would take developers away from more pressing issues, leaving some users wondering why resources are being spent on a gee-whiz toy instead of more practical tools, such as a better Facebook search engine.