Entries linking to boomlet
"sudden start or increase in commercial or other activity," 1873, sometimes said to be from boom (n.1) in the specific nautical meaning "a long spar run out to extend the foot of a sail" -- a ship "booming" being one in full sail. But it could just as well be from boom (n.2) on the notion of "sudden burst." The verbal sense "burst into sudden activity" seems to be slightly older (1871). Boom town is from 1883. The economic cycle of boom and bust has been so called since 1937.