Stamp Exhibitions began in the United States in 1888 when a small exhibit of stamps was included in the Boston meeting of the American Philatelic Association. Before that, stamp meetings were largely trading events with no formal displays. In 1889, J Walter Scott (of catalog fame) organized the first major stamp exhibition at the Eden Museum in New York. By the early part of the twentieth century, stamp exhibitions were common in every American city and most of us grew up on the model of our stamp activities being centered on going several times each year to a large stamp exhibition with a large dealers bourse attached. The financial model was that the fees from the dealers tables would underwrite the cost of the stamp displays. It was at exhibitions that most of us cut our philatelic teeth, seeing great stamps and collections and acquiring stamps for our collection.
Great philatelic exhibitions will be around for a while. The United States hosts a FIP sanctioned international show every ten years(the next is in 2016) and these are vast undertakings that shouldn't be missed by serious philatelists. But just as it has changed so many aspects of our and every other business, the Internet has forever altered the economics and appeal of stamp exhibitions. Exhibitions were once a place to see your stamp friends and to exchange information with other like minded collectors. Today, the Internet makes continual ongoing communication constant and devotees of the most esoteric areas can find each other at will. Once, stamp shows were the best place to find items for your collection. Today, Ebay alone offers each day more items than all the dealers at even the largest shows ever sold. And selling on line is cheaper than going to shows so there are fewer dealer tables which cuts the revenues of show promoters. Like newspapers, some stamp shows will straggle on in this new era, but the days of planning your months by what ex you will visit (Rompex, Nojex, etceterex) are nearly over.