Members of the IWW used to be known as Wobblies, and they were once a major force in America.
The IWW considered itself an industrial union as opposed to trade union. They believed all workers should band together in One Big Union to fight for the common interest of all workers, as opposed to fighting solely for the limited interests of a single union shop. They were the first union in the United States to organize across race and gender lines.
Not only was the IWW fundamental in winning the eight-hour workday cap as a standard for American workplaces, but through the Great Depression the union continued to push for the Four Hour Workday and the Four Day Workweek.
It used to be fairly common practice to bust unions by arresting organizers on trumped up disorderly conduct charges. So the wobblies also fought hard for Free Speech. The IWW used a method of direct action typical of their genius and numbers. Wobblies by the hundreds would stream into small mining or industrial towns, each taking to the soapbox, each quickly arrested. Soon the town's jails would fill to overflowing with radical unionists, and the small town could no longer afford its union busting.
Other unions (notably the AFL) villified the IWW: because they believed in direct action, they were more likely to go on a wildcat strike than sit down at the bargaining table. The yellow journalists of the day denounced the wobblies as immigrants and communists. (Most wobblies actually identified as anarcho-syndicalist.) As a result, the IWW suffered as victims of the first wave of anti-communist witch-hunts in America. Union members were lynched, deported, and imprisoned.
Remember that next time you work through your lunch break.