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How wired are we?

Global Internet usage passed the 1 billion mark in 2005. That's a lot of wired people.
Global Internet usage passed the 1 billion mark in 2005. That's a lot of wired people.
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Are you depressed? Isolated? Having trouble at work or at school? Do you sacrifice sleep to spend more time online? If so, then you might be suffering from Internet addiction. While this impulse control disorder isn't yet listed in the Diagnostic and Statistical Manual of Mental Disorders, the bible of sorts for mental health professionals, more people complaining of symptoms of compulsive Internet use are showing up at mental health clinics. PCU, or pathological computer use, is a proposed diagnosis for the manual's upcoming edition [source: Busko, Tech Target]

While you may not be constantly connected to the Internet, which is what we mean when we say "wired," you obviously are not immune to its attraction or you wouldn't be reading this article. Official or not, the existence of an Internet-related mental disorder does highlight the pull of the online world and its viral spread around the globe. It also raises a good question: Just how wired are we?

Are you so attached to your computer that you panic if your e-mail is down for a few hours? Do you really need eHarmony to find that special someone? Can you remember the last time you licked a stamp?

In this article, you'll follow the rising use of the Internet for everything from buying a pair of shoes, to ordering pizza, to watching last night's episode of "Lost." Heck, you could even self-diagnose your own Internet addiction with the preponderance of online health information.

­The Internet has come a long way since it entered the scene in the 1990s. While Internet usage in the United States tends to be skewed more towards the affluent and well-educated, overall trends are starting to mimic the general population [source: Harris: Four]. In 1995, only 0.4 percent of the global population had Internet access -- just 16 million people. Ten years later, in 2005, global Internet use passed the 1 billion mark and more than 15 percent had access. As of March 2008, that number was approaching 1.4 billion, or more than 20 percent of the world's population [source: Internet World Stats].

What are all those people doing online? Because they're not all reading this article. Find out on the next page.