The technology seen around the office in Mad Men is pretty basic compared to the appliances employees working at Sterling Cooper would encounter if they were working there today. That’s why it is so funny to the audience of Mad Men when Joan remarks that the typewriter looks intimidating and advanced. The typewriter; in reality, was a pretty simple device that helped drive offices like Sterling Cooper’s for a good part of the 20th century.
Christopher Sholes invented the modern typewriter in 1866. The modern typewriter was the first typewriter with a universal keyboard. Shortly after this invention hit the marker, one of Sholes associates changed the keyboard to the modern QWERTY design, which caused the keys to jam less. The typewriter was a tough gadget to market at first, for a wide variety of reasons: the unwillingness of businesses to move on from handwriting, the economic stagnation of the time and the price, which was around 100 dollars (http://www.smithsonianeducation.org/scitech/carbons/typewriters.html). With a price like that, the typewriter was worth more than most modern computers, with prices adjusted for inflation. Typewriters were also tough to use, because if a typist made more than a few mistake they would have to trash their current document and start all over with a new one.
Around the time the first season of Mad Men takes place, (1960s), (http://www.mit.edu/~jcb/Dvorak/history.html) the first electronic typewriters were being introduced to the market. Sterling Cooper doesn’t use these in the first season, but they would have been one of the companies that would have adopted them to their offices.
Without the typewriter, offices like the one in Mad Men would have had a much harder time producing documents, and offices would have been a lot less productive. Despite the cro-magnon-like appearance that the audience takes away from the device today, it was definitely useful for the era.