Block explorers are tools that maintain an index of transactions and their relationships to each other, allowing fast look up of information useful to wallets, users, and developers.
Although many users find block explorers to be a convenient way to look up information about their own transactions, their searches may be logged and used to associate their transactions with their IP address, browser cookies, and other identifying information. The large indexes block explorers keep also aren’t expected to scale well as the size and complexity of the block chain grows.
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