Documents that result from, for example, Two Takeoff Meetings encourage people to band together behind some ideas.
Most notably, the Snowbird Workshop's Manifesto was posted with a form (due to Ward Cunningham and "Pragmatic" Dave Thomas) that allowed people to sign up as supporters. The number of people who did revealed a groundswell of support for the ideas, and also amplified that groundswell.
The LAWST1 document also spread "virally," though less so. It got publicized via mailing lists.
It's possible that I misremember, that the real "takeoff" for what came to be called "context-driven testing" was later, when that movement got a name and its own manifesto-like document 
. But I remember an upsurge of interest and credibility associated with LAWST1.