An address is just a place coins can be sent. One company can control millions of them, and one exchange address can hold the coins of millions of customers. So counting addresses tells you little about counting people.
From addresses to entities
Analysts group addresses that appear to share an owner into clusters, called entities. The classic clue on Bitcoin is common-input spending: when several outputs are spent together in one transaction, one party usually holds all the keys. Clustering is an inference, so it gets things wrong, and different providers draw the lines differently.
Labels
A label says a cluster belongs to a named organisation, such as an exchange or an ETF custodian. Good labels come from what those organisations publish about themselves: proof-of-reserves address lists, filings and their own announcements.
At CryptoKeyhole we label organisations only and publish aggregates. We don't track or profile individuals, and addresses inside a transaction stay plain text on the explorer. That choice has a cost: where an organisation publishes nothing, its coins stay unlabelled and the chart says so.
What to watch for
When you read an indicator built on entities or labels, ask two things: how much of the supply does it cover, and what happens to coins the method can't place? A chart that quietly leaves them out reads very differently from one that states the gap.