Pneumatics can be traced back to Hero of Alexandria in the 1st century AD. The Victorian Internet used capsule pipelines to transmit telegraph messages, or telegrams, to nearby buildings from telegraph stations.
While they are commonly used for small parcels and documents, they were originally proposed in the early 1800s for transport of heavy freight. It was once envisioned that massive networks of these tubes might be used to transport people; Alfred Beach's first New York Subway system used this principle (but was only 300 feet long!).
It was also speculated that a system of tubes might deliver mail to every home in the US. A major system in Paris was in use until 1983 when it was finally abandoned in favor of computers and fax machines.
Typical applications are banks and hospitals. Many large retailers (such as Home Depot or the Price Club in the US) use pneumatic tubes to transport checks or other documents from cashiers to the accounting office. One modern system lists a speed of 25 feet per second.
Pneumatic tubes were featured in Edward Bellamy's Looking Backward which envisions the world of 2000 as filled with tubes; in the movie Brazil; as well as in the (1999) television series Fantasy Island.
http://www.attsystems.com Air Tube Transport Systems
http://zapatopi.net/pneumatic.html Proposal for pneumatic tubes for transporting people
http://future.newsday.com/1/fbak0115.htm Pneumatic tubes for postal service