consumers we establish see-saws between consumers and advertisers. Entry of a lower-quality platform increases consumer surplus …, but decreases advertiser surplus if industry platform profits decrease with entry. Merger decreases consumer surplus, but …

reduces the competitive pressure incumbents face which depresses productivity. Contrarily net entry strengthens competition … that focuses on two industrial features (1) slow firm entry/exit and (2) firm pricing that depends on the number of … tractable DGE model of endogenous firm entry/exit and endogenous markups. …

, fails to draw on the most relevant fields of economics; entry is often a misanalyzed afterthought; official information …