Defining Aggregators – Stratechery by Ben Thompson

-Zero Marginal Costs For Serving Users

Level 3 Aggregators: Zero Supply Costs: Level 3 Aggregators do not own their supply and incur no supplier acquisition costs (either in terms of attracting suppliers or on-boarding them). Google is the prototypical Level 3 Aggregator: suppliers (that is, websites) are not only accessible by Google by default, but in fact actively make themselves mor... See more

Level 1 Aggregators: Level 1 Aggregators acquire their supply; their market power springs from their relationship with users, but is primarily manifested through superior buying power. That means these aggregators take longer to build and are more precarious in the short-term.

-Direct Relationship with Users

Aggregators have all three of the following characteristics; the absence of any one of them can result in a very successful business (in the case of Apple, arguably the most successful business in history), but it means said company is not an aggregator.

Because aggregators deal with digital goods, there is an abundance of supply; that means users reap value through discovery and curation, and most aggregators get started by delivering superior discovery.

Level 2 Aggregators: Supply Transaction Costs: Level 2 Aggregators do not own their supply; however, they do incur transaction costs in bringing suppliers onto their platform. That limits the growth rate of Level 2 aggregators absent the incursion of significant supplier acquisition costs.

This means that for aggregators, customer acquisition costs decrease over time; marginal customers are attracted to the platform by virtue of the increasing number of suppliers. This further means that aggregators enjoy winner-take-all effects: since the value of an aggregator to end users is continually increasing it is exceedingly difficult for c... See more

-Aggregators incur none of these costs: