Smartphones are considered "smart" due to four key features: 1) Operating systems that allow for a wide variety of applications and fast performance. Popular mobile operating systems include iOS, Android, and Windows. 2) Applications that provide functionality like personal assistants, photo editing, entertainment, and more that can be downloaded from app stores. 3) Web access that allows for high-speed browsing on mobile internet connections. This enables activities like online learning and communication with clients. 4) Messaging capabilities that go beyond basic text, allowing users to send emails and access instant messaging without needing a computer. These features allow users flexibility and mobility.