Pneumatic mail and flows of information made explicit

Main system My hotel last week in San Francisco had this fascinating mail transit system that allowed people to drop letters in this pneumatic-like system parallel to the elevators. You can leave your letter at the floor you're located (picture above) and it drops down the collecting box downstairs.

Mail system

Why do I blog this? fascination towards this sort of communication system (as a first step in the sending of snail mail) that embeds an intriguing physical component. However, I haven't seen any mail/postcard going through it apart from the one I sent the day after I discovered such a device.

What I find interesting here, although it's rarely employed today, is the possibility to visualize the information flow. To some extent, it makes explicit an rather invisible phenomenon (communication). A sort of similar (and more quiet) version of Palantir (the vizualization of facebook data on the globe):