Linked from
The 26 pages that link to Binary number, each with the reason it gives.
Machine codeNarrower topic: Machine-code encodings are represented as bit patterns.
Compact discNarrower topic: The disc’s digital data ultimately consists of binary values.
DigitizationNarrower topic: Binary values are the basic symbols used to encode digital information.
Pioneer plaqueNarrower topic: The plaque’s labels and measurements rely on binary notation.
XNOR gateNarrower topic: XNOR inputs and outputs are binary values.