To jump on the bandwagon is to join a popular movement, cause, or trend — often not from genuine conviction, but because it seems advantageous or socially safe to do so. The phrase carries a slight implication of opportunism: you are not a pioneer but a follower, and you are joining because others have already made it safe. Technology companies jump on the bandwagon when they copy a competitor's successful feature.
In 19th century American political campaigns, candidates would literally hire a horse-drawn wagon carrying a band to drive through towns and attract attention. The music drew crowds and gave the impression of popular momentum. Local politicians and celebrities were invited to climb aboard the bandwagon — to be visibly associated with the candidate and his apparent popularity. Doing so signalled support and was expected to benefit the rider's own reputation.
The circus promoter P.T. Barnum used elaborately decorated band wagons prominently in his circus parades from the 1840s. His use made the bandwagon a symbol of spectacle and crowd-following. The political metaphor was well established by the 1848 US presidential election and became a standard phrase in American political reporting. It has since spread globally as a synonym for any popular trend.
The phrase is mildly critical but not always harshly so. Describing a company as having jumped on the AI bandwagon implies they are following a trend rather than leading it, but not that they are doing anything wrong. Context determines how critical the phrase is.
Going against the grain, bucking the trend, or being an early adopter (before something is popular). A contrarian deliberately avoids bandwagons.