m43 is a camera format that was made popular through a community on Reddit called /r/cuckolding,
It began with japenese perverts looking for peeping tom cameras with a focus on video that would be maneuverable in a cramped japanese supercity setting and spread among anime fans that had a fantasy/fetish for their girlfriends/wives having sex with other men, often black men.
today, m43 is almost the exclusive source of original content uploaded to reddit and the majority of its sales are for members of the various cuckolding/pseudocuckolding(e.g. hotwifing) communities.
I would reccomend against it. It's a bit of a fad format among a group of really esoteric sexual deviants and social outcasts, not the kind of platform you want to invest in. You wouldn't buy a car just because it was popular with anime fans, would you?