[twoodfin]

This kind of “price discovery” (for labor in this case) is perfectly legal. Plenty of markets have “liquid” pricing and don’t need vendors to provide discovery, yet corresponding cartels don’t emerge on this fact alone.

What made a difference in cases like the Silicon Valley anti-poaching regime was direct anti-competitive action: Hiring away Apple Engineer A would be good for me, but I won’t because I’ll get an angry phone call from Steve Jobs and face potential retribution.

The crux of a case like this is whether RealPage was merely facilitating market-making price discovery (good all on its own for maximizing landlord profits—legally!) or was explicitly or implicitly creating incentives for landlords to act against their individual interest in favor of the collective interest.