Scalability in technology systems refers to the capability of a system to handle an increasing amount of work, or its potential to be enlarged to accommodate growth. It is crucial for ensuring that applications can manage higher loads without compromising performance. Scalability can be achieved through horizontal scaling (adding more machines) or vertical scaling (upgrading existing machines), allowing businesses to adapt to changing demands. Building scalable systems is vital for long-term success, enabling organizations to respond swiftly to user needs and market fluctuations.