To bring (a system, etc.) online; to promote to an active or running state.
Of a system: connected (generally electrically) to a larger network.
Available over, or delivered from, the Internet.
Connected to the Internet.
Available on a computer system, even if not networked.
Of a system: active, particularly building facilities (such as power) or a factory or power plant.
While online; while in a running or active state, or connected to the Internet.