Nonsense. Every economy is planned... with many plans, not a central plan.

This is yet another plan. It is the combination, coordination and sometimes just luck that these plans align to mutual benefit that make some better than others. If this one matches enough individuals' plans to line up, then it will become a means to their ends, and thus find value.

You're right about the bit of people being forced to take part... but that doesn't make it a central plan, that makes it a part of a network of interconnected plans from which one may freely exit (thereby allowing a corrective element).

Now... internally, companies can be "centrally planned" and often are... but here the company is running a set of general ground-rules around the structure, and letting consumers vote on content. As it should be.