What is an "Internet user" for those creating statistics?

We have all seen these statistics representing different aspects of the Internet economy.

Even basic numbers such as "Internet users" can oftentimes be misleading if we do not have a clear understanding of the definition of what they try to represent. How to promote access and create effective programs if the most essential question of how many people are already included cannot be clearly defined?

A visual representation of Internet connections

This is one of the interesting discussions of Week 2 of the Internet Governance Capacity Building Programme - IGCBP group ACP Africa D, tutored by Ulemu Nyasulu.

Here's the comment made by one of the course participants that triggered a rich discussion:

QUOTE
...My point here is that the definition of an Internet user is too vague right from the start. such being the case its a wonder how any valid approximations can be made.

Perhaps we need to define which services on the Internet count? This is particularly important with so many people in developing countries having mobile access. When can a mobile user be considered an Internet user? Does using a mobile application that periodically accesses the internet count? Does using only Voice over IP count? How about sending an sms that ends up in an email inbox, should that count as Internet usage?

Off the top of my head, I would propose that an Internet user is only content when they contribute a minimum amount of internet traffic.

Naturally the amount of traffic contributed can be different whether the individual is coming from the developed or developing world. The immediate problem I see is that devices can easily be bundled in this definition (unintentionally though).

I guess we have people representing Telcos and regulators out there. What metrics are used in different countries? How do you acquire such statistics? What are the statistics in your respective countries and do they appear to be valid?
UNQUOTE

It was agreed among course participants that a definition is complex, particularly when mobile technology is used.

While different points of view were presented on how many minutes or hours a day would be adequate to consider one as an Internet user, another participant proposed that anyone who uses Internet services for whatever reason for whatever time period should be included in the definition. To illustrate the point, this commentator made an analogy with telephone subscribers