The power of the network effect — the ultimate moat
Chapter 1 of 12 · 5 min
Why winners take all in network markets
10x Insight
Metcalfe's law: value ∝ n².
What is a network effect?
A network effect arises when the value of a product or service increases for each user as more use it. Classic example: the telephone. A phone is worthless if you are the only user. Two phones = a little value. 100 phones = useful. 1 million phones = indispensable. Every new phone user increases the value for all existing users — network effect. This is fundamentally different from traditional products. A chocolate biscuit is worth the same no matter how many others eat chocolate biscuits. A phone becomes more valuable with every new user. The difference is enormous economically. Traditional companies grow linearly (each new customer = 1 unit of value).
Network companies grow exponentially (each new customer increases the value for all existing ones). Metcalfe's law: the value of a network ∝ n² (the square of the number of users). 10 users = 100 units of value. 100 users = 10 000 units of value (100x increase for 10x users). This is why network companies can go from 0 to 1 million users in a few years and dominate the market — winner takes all. Sweden has several network moat icons: Blocket (dominant marketplace), Spotify (music streaming), Klarna (payments), Tradera (auctions).
💡 INSIGHT
Metcalfe's law: value ∝ n². This is why network companies win 'winner-takes-all' markets. The first to reach 'tipping point' (typically 30% market share) wins 90% of the market. Blocket reached tipping point in 2005 — has since dominated the Swedish secondhand market for 20 years.
Three types of network effects
There are three main types of network effects. Type 1 — TWO-SIDED network: buyers and sellers. Blocket (sellers of used goods + buyers)
📖 DEFINITION
Two-sided network = platform where two sides (seller/buyer, artist/listener, merchant/consumer) meet. The value increases for both sides as more participate. Data network = algorithm improves with more user data. Standard network = technical standard becomes more valuable with more users.
Why network effects are the strongest moat
Network effects are the strongest form of moat for four reasons. Reason 1 — self-reinforcing: every new user makes the network more valuable, which attracts more users. This is a virtuous cycle that competitors cannot break without massive subsidies. Reason 2 — winner-takes-all: in network markets one player tends to win 70-90% of the market. Blocket has 90% of the Swedish secondhand market; Google 92% of search; Facebook 70% of social media. Reason 3 — low marginal costs: network companies can scale to billions of users at low extra cost. Spotify has 500 million users but adding one more user costs almost nothing. A traditional company must build a new factory to grow. Reason 4 — data moat: network companies accumulate data that becomes a moat in itself. Spotify knows what 500M users listen to — no competitor can match this data without 500M users. This is the 'chicken-and-egg' problem — the competitor needs users for data, and data to attract users. Of these four reasons, network effects are the most sustainable moat — once established it is almost impossible to break. But: network effects take time to establish and many companies die before reaching 'tipping point'. As an analyst: identify companies NEAR tipping point or ALREADY dominant. Avoid companies far from tipping point — they have high risk of dying.
⚡ KEY INSIGHTS Network effect = the value increases for each user as more use it Metcalfe's law: value ∝ n² — exponential, not linear Three types: two-sided > standard > data (hardest to break = two-sided) Winner-takes-all: 70-90% market share for the dominant player 2