EBay also started by dominating small niche markets.

When it launched its auction marketplace, the product worked well for intense interest groups, like Beanie Baby obsessives.

Once it monopolized the Beanie Baby trade, it continued to cater to small-time hobbyists until it became the most reliable marketplace for people trading online.

Sometimes there are hidden obstacles to scaling. The auction marketplace lent itself to natural monopoly because buyers go where the sellers are and vice versa.

EBay found that the auction model works best for distinctive products like coins and stamps.

It works less well for commodity products: people don’t want to bid on pencils or Kleenex, so it’s more convenient just to buy them from Amazon.

EBay is still a valuable monopoly; it’s just smaller than people in 2004 expected it to be.

The most successful companies first dominate a specific niche and then scale to adjacent markets.