Addiction is behavior that controls you. Absent an outside chemical or substance involved, as with social media, it's actually you - your impulses, your pleasures, your anxieties, your fears, your preferences - taking center stage over your better judgment ore reasoned decisions.
It seems to me that the trigger for so much of this technology activity is related to impulse control. An impulse is a thought that prompts action. Impulsivity is where you act on thoughts in the short term whether or not you will benefit in the long term. In the psychology world there is something called impulse control disorder, and it comes into play with compulsive behaviors such as stealing, pathological gambling, hair pulling, skin picking, and nail biting. In each the thought behind the impulse is to provide some sort of momentary gain, a hit if you will. The theft of an item or gambling brings relief from the mounting pressure to return to the behavior. Pulling your hair, picking at your skin, or biting your nails is a physical distraction to a psychological distress.
In each of these there is an imperative to the impulse. I always feel a compulsion to answer my phone, no matter how peaceful or noninvasive the ringtone is. There is an inner urgency that has nothing to do with the actual content of the call. The impulse is within me, not within the call itself. Many of us keep answering the siren call of technology with increasing urgency. We have imbued our devices with elevated importance and have contributed to the constant state of crisis about what we might be missing if we're not online or connected. Our impulse is to always say yet to our technology in order to experience a short-term benefit even if such use results in a long-term loss. But every yes we give technology moves us closer and closer to that line between activity and addiction.
The above is excerpted from chapter 3 in #Hooked: The Pitfalls of Media, Technology and Social Networking by Dr. Gregory Jantz.