Rusty
Purveyor of Fine Weaponry
Minor Factions have zero visibility compared to the in-your-face nature of Major Factions, and in my experience the only successfully large minor factions are the ones that are attached to a Major Faction (you know, Subfactions), or minor factions that are gearing up to go Major.
Hard to overstate the visibility thing. Major factions and their subfactions have presence. They're the most active recruiters, and they're the easiest to find information on, either through official sources or word of mouth. Minor factions that don't want to make a splash in the map game are barely a blip on the radar.