MMO-Stock is an online rating and directory for free-to-play multiplayer game projects and servers. It brings together communities and listings for popular titles including World of Warcraft, Lineage II, MU Online, Perfect World, Aion, and RF Online, alongside a broad selection of other online games. The platform helps players discover servers and projects, compare their standing in audience-based rankings, and find communities that match their interests.

It also gives game project operators a place to present their servers and participate in a shared catalogue, supporting fair competition across different games and regions. MMO-Stock describes itself as an international service for projects around the world and aims to foster a multilingual community focused on useful, trustworthy information about the massively multiplayer online games industry. Site features include game and project sections, server listings, voting and ranking tools, project news, registration, and account sign-in.

The platform also provides advertising placements and paid services, with published advertising, privacy, and refund information, plus a technical support contact for users and project owners