Fundamentals

Network Effects: What They Are, How They Work, and Why They Matter

By Daniel Sardá · Published on October 14, 2026

6 min read1,131 words

Network effects arise when the value of a good or service changes with the number of people who use it. Understanding them helps explain the growth of networks and platforms without confusing size, quality, and market power.

Imagine that you are the only person with a telephone. The device may be excellently designed, but it is nearly useless for its main purpose: there is no one to call. When another person connects, both gain a means of communication. With every additional compatible user, the possible connections increase.

That change in value brought about by other people's participation is a network effect. It does not simply mean that a physical or digital network exists. Nor does it describe every advantage enjoyed by a large firm. More precisely, it means that the utility a person gets from a good or service changes as the number of users of the same system—or of compatible systems—changes, as Michael Katz and Carl Shapiro explained in their classic work on compatibility.

Key idea: A network effect exists when other people's participation changes the value each user receives, not merely when a product becomes popular.

How a network effect takes shape

The mechanism can be understood as a chain. First, someone adopts a service. Their participation expands the options available to other users. That greater usefulness may attract further adoption, which in turn makes the network more attractive.

This feedback helps explain why some networks grow quickly once they reach critical mass. The term does not point to a universal number of users. It describes a participation base sufficient to sustain adoption in a particular market.

The process is not automatic, however. People also weigh price, quality, ease of use, compatibility, and alternatives. Their expectations matter: no one will want to adopt a network if they expect others to abandon it soon. A broad user base can be an advantage, but it cannot indefinitely compensate for a poor service.

Direct and indirect network effects

Network effects do not always operate in the same way. It is useful to distinguish two main forms.

Direct effects

An effect is direct when each additional participant immediately expands the possible interactions within the same system. The telephone is the clearest example: the more compatible contacts there are, the more useful the connection may be to each person.

What matters is not how many devices are manufactured, but the ability to communicate with other users. This is why compatibility between networks can extend the effect beyond a single provider.

Indirect effects

An effect is indirect when growth in one group attracts complementary goods or participants from another group, and those in turn increase value for the first. In a digital marketplace, for example, more buyers may attract more sellers; a wider range of offerings may then attract new buyers.

These platforms connect distinct groups whose decisions are interdependent. The literature on two-sided markets, developed by Jean-Charles Rochet and Jean Tirole, shows why a platform must create value for both sides rather than simply count users as if they all played the same role.

Key idea: In a direct network, what matters is how many compatible people can interact; in a two-sided platform, the balance between different groups matters as well.

More users do not always mean more value

Network effects can also be negative. If too many participants compete for a limited resource, create noise, or overload the system, each user's experience may worsen. A congested road, a community overwhelmed by irrelevant messages, or a market with too many sellers and too few buyers illustrate different forms of deterioration.

Even within the same platform, growth can benefit one group while harming another. More sellers may improve variety for buyers, yet also intensify competition among sellers. The necessary question is always: which participants are joining, and whose value is changing?

What is not a network effect

Several economic forces can accompany network effects without being the same thing.

• Economies of scale: These arise when producing more lowers average cost. A network effect, by contrast, operates through the utility users receive. A factory can have economies of scale even if its customers gain nothing from having more customers.
• Switching costs: These are the sacrifices involved in moving to another option, such as learning a new system or transferring information. They can reinforce continued use of a network, but the mechanism differs: one depends on other participants, the other on the cost of leaving.
• Quality: A large user base does not by itself prove that a product is better. Adoption may also reflect expectations, compatibility, or difficulty switching.
• Concentration: A market with few providers is not enough to identify the cause or measure durable market power. It is necessary to examine conditions of entry and the real ability to choose.

Warning: Confusing size with quality or market power obscures the important questions: why users stay, what alternatives they have, and how costly it is to switch.

Network effects, competition, and choice

An established network can be difficult to challenge. A new competitor may have to do more than offer a good product: it may need to persuade many people to adopt it in a coordinated way. That barrier can favor concentration, but it does not make monopoly inevitable.

Differentiation can allow an alternative to serve unmet needs. Interoperability allows users of different systems to communicate or exchange data. Multihoming—using more than one service—reduces the need to choose a single network. The OECD has examined how portability and interoperability can make switching and entry easier, though they do not by themselves guarantee effective competition.

Innovation and competition can also alter an advantage that once seemed secure. A new technology may shift the relevant standard of compatibility or create a different network. Analysis of economic competition must therefore consider not only how many participants each service has today, but also the possibilities for entry, differentiation, and exit.

From a perspective of economic freedom, network effects show how voluntary cooperation can create value without central direction: each new participant can potentially benefit others. But that observation does not justify privileges for a company, nor does it establish that every intervention will improve the outcome. An advantage gained in the market is not the same as a legal monopoly. Before judging a network, it is worth examining consumer choice, switching costs, compatibility, and market contestability.

A powerful advantage, not an inexorable law

Network effects help explain why some technologies and platforms become useful quickly and why others struggle to gain traction. Their core is simple: the decisions of some users change the value available to others.

But size does not decide everything. A network can lose usefulness through congestion, fragment because of a lack of compatibility, or be challenged by an alternative that lowers barriers to entry. Understanding the phenomenon requires looking beyond the number of users and asking what value they create for one another, what choices they retain, and how open competition remains.