If they advertise increased click-through rate and they increase it, what stops them from claiming they fulfilled their end of the bargain? It could even be click bots.
Maybe that's a new platform company strategy: build a bunch of low-volatility/low-margin enterprise products for long term revenue generation, then fund a bunch of shadey operations as products to be pools for off-the-books bonuses and incentives.
I agree with your larger point, that LinkedIn isn't really accountable to anyone; the Microsoft shareholders don't care what LinkedIn does.