Collecting societies like PRS and MCPS operate collectively, issuing blanket licenses to users and distributing royalties to all members according to usage data. They handle specific rights in specific territories - PRS for UK performing rights, MCPS for UK mechanical rights. Publishers work individually for their writers, providing a much broader service. They ensure registration with societies worldwide (not just UK), chase royalties from sources societies don't cover, provide creative services, and actively create new exploitation opportunities for your music. While societies are essential infrastructure for collective licensing, publishers are your personal representatives in the global music business. Most professional writers need both - society membership for collective licensing, publisher support for everything else.