[tim333]

Predatory pricing is "below-cost pricing allows a dominant competitor to knock its rivals out of the market and then raise prices to above-market levels for a substantial time." It would be hard to argue that G+ is giving away space to knock Facebook out of the market and then charge for G+. Classic predatory pricing is things like British Airways driving Laker Airways bust so they could jack prices on the London NY route.

[ZeroGravitas]

It's the rates on advertising that Google could increase if it knocked out a competitor,