How do worldpackers work?

Could you please explain to me how worldpackers operate? I'm curious about the mechanism behind this platform that connects travelers with hosts around the world. Do travelers pay for their accommodations, or is it more of a bartering system where they provide labor in exchange for free stays? Are there any specific requirements or guidelines that both parties need to follow? I'm eager to learn more about the ins and outs of worldpackers and how it can benefit travelers like myself.