[willturman]

Word of mouth, independent websites, newsletters, blogs, community organizations, religious organizations, political organizations, amateur radio broadcasts/transmissions, neighborhood meetings, festivals, conferences, meetups, cultural traditions, leaflets, town criers.

[hackyhacky]

Many of these (word of mouth, community organizations, religious organizations, meetups, neighborhood meetings) don't work beyond the local area.

Many of these (radio broadcast, independent websites) aren't accessible to non-technical people.

Many of these (cultural traditions, town criers) are obviously unserious.

[willturman]

Every single one of these has been effectively used to organize at geographic scale within this most recent century before "non-technical" even existed as a possible descriptor of a human being.

Many of them necessitate going outside, which may present an imaginative hurdle.