When I started training parkour in early 2006, it was still very underground. People would find stories online of people who can climb walls, they’d see pictures of people leaping headfirst over picnic tables, or they’d download grainy videos (Youtube was less than a year old at this point) of Russians climbing through bombed out ruins.
Once you heard about parkour, you would inevitably find one of the two major sites - Parkour.net or American Parkour. And maybe, if you were really lucky, you’d find someone on the forums who lives within an hour or two of you. You’d meet up with this stranger from the internet, usually in a public park, or at a playground, or at a local college, and you’d start training.
We called these events where people would meet up and train together “jams.” Sometimes they’d be regularly scheduled (Meet at Manhattan Square Park in Rochester, NY every Saturday at 2pm), often they’d be scheduled just a few days in advance via posts on the forums (“Who wants to go to Zen Park at 4pm tomorrow?”). Jams were free, and people would come to train with, and learn from, each other.
As parkour got more popular, some of the more advanced traceurs (someone who trains parkour) started teaching classes and charging money. This caused a huge divide in the community.