The Chinese are thinking addiction to social media is serious enough that they've created a series of support groups throughout the country to ween people off of it. You could also view these as indoctrination camps, but the idea is there.

And, coming from experience, if someone has an addictive personality, they can become addicted to anything, particularly when it contains such a clear emotional component to it.

I'm of the mind that while 'addiction' is certainly an overused term, the social web is causing addictive-like behavior and a loose definition of the term probably applies. I think the most active social web participants are still in the early-adopters realm, largely because I don't consider these new technologies to be ubiquitous enough to warrant such intense participation for the masses.

Now, older technologies went through their growing stages, and as they've become ubiquitous they've slid themselves into EVERYONE'S lives across all levels of expertise, and settled into useful, common, frequent-use technologies. Social web tools and environments will get there too, but I still see them as somewhat disruptive to the layperson's typical social and professional behavior. You have to make an effort to deeply involve yourself. To get to the pulse of these tools, you find yourself choosing them over other activities. I think as interactive behavior shifts towards social web tools (that I also think will replace old technologies like the phone systems, texting, and email) you'll see this type of communication embed itself as more than an opt-in environment. This can only happen when it's incredibly easy to participate...when it doesn't require acting like an addict.