The company has 'plugged into' the international market. [=the company has become connected to the international market; the company has begun to do business in the international market]
His friends are 'plugged into' the city's music scene. [=his friends are actively involved in the city's music scene]
The computer program will take data from these sources and automatically 'plug' it 'into' the equation.
(..) Skynet begins to learn at a geometric rate. It becomes self-aware at : a.m. eastern time, August . In a panic, they try to pull the plug. Skynet fights back. Yes. It launches its missiles against targets in Russia. Why Russia? They're our friends now. (..)1991 Terminator 2: Judgment Day