Occupy educated and politicized a generation of activists who spilled out into scores of loosely allied movements and American life. They represent a massive resource for every progressive effort that’s followed. Here’s the short story:

Occupy appeared to trace a meteoric trajectory across the political skies in the fall of 2011, emerging out of what looked like a marginal event in December, then spreading across the United States, then evaporating when ruthlessly cleared out by police in November. The people animating those hundreds of Occupations seemed to come from nowhere and disappear right back into nothingness.

Both of those images are wrong.

In New York City, Occupy Wall Street was initially staged by a group of activists who’d previously staged actions at City Hall, even constructing a shorter-lived occupation that summer, “Bloombergville.” When the Occupation settled in, experienced activists from many different well-established groups and movements flowed into Zuccotti Park, bringing their own histories and commitments. Labor unions supported the Occupation, sometimes because of political allegiance, sometimes hoping to generate numbers to ward off harsh policing, and some just hoping to benefit from the spotlight Occupy commanded.

The Occupations developed teams of coders with laptops, creating global streams for their meetings and events, finding an audience even when mainstream media wouldn’t cover them. Occupy reached people who never made it to an Occupation.

When Occupy Wall Street became the most visible progressive action in town–and in the country–lots of people and causes wanted in on it.

Occupations everywhere were based on prior activist networks, and developed distinct characters. In some cities, there was more than one Occupation, each with a distinct political style and focus. In some cities, labor was a strong presence, in others environmental concerns were visible; housing was a core issue in some places, but not others.

Political novices dropped in too, sometimes for a night or two, sometimes for a particular protest, sometimes sleeping outside for weeks and engaging in endless meetings about political strategy and maintaining the encampment.

Activists with different concerns and backgrounds knocked up against each other, repeating speeches with a human microphone, and building broader coalitions and personal networks. Groups maintained libraries, organized site maintenance and cleaning, and made and shared and talked about meals.

Occupy never developed a unified plan for what to do when police cleared out the camps; there was no exit strategy. In New York City, some veterans obsessed about the tactic, desperately trying to reenter Zuccotti Park.

But others spilled out into other movements. When a neighborhood watch volunteer in Florida killed an unarmed Trayvon Martin, long time activists had more extensive contacts with a broader range of people ready to protest racialized police violence, and certainly cynical about policing in America. In Minnesota, Occupy Homes campaigned against evictions. In New York, one-time Occupiers developed a mutual aid approach to recovery from a hurricane, Occupy Sandy. Climate change crusaders targeting the Keystone Pipeline include Occupy veterans–and others who saw the encampments on streaming networks–or even television news.

First time activists were no longer novices; they left the Occupations having endured an odd and powerful education in progressive politics and activism. Experienced organizers left with broader networks to activate and longer contact lists of allies. Sympathetic spectators learned not to take for granted the inevitability of current political arrangements, and got a sense of what might be possible in the future.

The Occupy wave, demographic and ideological, will be passing through American politics for the next several decades.

Score a win for changing the lives of participants (and spectators).