Quantities can be used rather than prices, as this particular piece points out, so my original point remains: price signals aren't necessary for planning. Beyond that, however,  there always seems to be two presumptions that always accompany this kind of debate: that we have to optimize for production (couldn't we just as easily optimize for more equitable distribution, or within environmental constraints?), or that we're necessarily going to face the problem of top-down control. As regards the problem of determining preferences, meta-data combined with software bidding agents strikes me as one way to deal with this obstacle, along with occasional non-automated inputs (e.g. something akin to shareholder votes). Worker cooperatives are fine, but socialism still has a vested interest in replacing competition with coordination and planning. You pose this in your article as some kind of monumental choice between markets and bureaucrats; it can (and should be) neither.