Dopamine jolt behind internet addiction
The effect on the brain is similar to what makes drug addicts reuse cocaine
Kristen Lindquist, professor of psychology at the University of North Carolina, Chapel Hill, says social information feels intrinsically rewarding to people. We get a jolt of dopamine when someone “likes” our Facebook post or retweets our Twitter link. Over time, the effect on the reward centre in the brain is similar to what makes drug addicts go back for another line of cocaine.
** EDITED to reflect edits to the question and discussion in comments. **
Everything in the article seems credible, and doesn't seem to contradict other sources. It does seem guilty of sensationalising the subject because there doesn't seem to be any unique link here - you can could equally draw similarities with love, food, sex, sports or many other things.
Certainly we can say there are some similarities between facebook feedback and cocaine use which are backed up by scientific studies, such as this study published in the journal Frontiers in Human Neuroscience in which researchers used Functional MRI scans to establish that positive feedback on Facebook does stimulate the reward centre in the brain.
Positive Facebook feedback seen as a 'reward' in brain
The findings of the study revealed that participants who gained positive feedback about themselves showed stronger activity within the nucleus accumbens compared with when they saw another person receiving positive feedback. This corresponded with the subjects' intensity of Facebook use.
Cocaine use and many other things also stimulate the reward area of the brain. This article in the Journal of Advanced Practive Nursing says that love, cocaine and gambling are all similar:
“When thinking about your beloved, there is intense activation in the reward area of the brain — the same area that lights up when you take cocaine, the same area that lights up when you win a lot of money.”
The drug achieves its main immediate psychological effect—the high—by causing a buildup of the neurochemical dopamine.
With the development of brain-imaging technologies it has been discovered that the 'highs' cocaine users experience is directly correlated with the degree to which cocaine binds to dopamine transporters (molecules which allow for the re-uptake of dopamine), especially in the nucleus accumbens.
What I've established with these references appears to support some similarity of the immediate effects. I don't want to draw conclusions which are not in the sources, and I'm not sure whether they are adequate to support the idea that the cumulative effect leads to addiction; perhaps we need more references to support that or perhaps an expert in addiction could confirm that this conclusion can be drawn.
TL;DR There is scientific evidence of the effect on the brain and there are some similarities to cocaine use.