Does it matter?

If you assume a one-to-one correspondence between CDs and users; either for Ubuntu or AOL, you are doomed.

As an explanation, newspapers (the actual paper kind) are typically bought by one person.

In some cities, only that one person will actually read it. In other cities it could be ten. This is known as readership figures.

They vary by newspaper, by cities and even area within cities. But, in general, the average readership figure is between 2 - 3 people (animals are typically not counted).

Now with CDs, and specifically, the ShipIt program -- you have a self-selected set of people who already use Linux AND they are interested in advocating it (in general, there will always be occasional people who just keep them to themselves for whatever reasons).

We can be conservative and assume a "CDership" of 1.5

Assuming production runs of 100,000 per Ubuntu release (Ubuntu, Kubuntu, Xubuntu, etc.) and then also architecture (i386, x86-64, PPC, etc). means probably close to 600,000. Over a number of releases (since 2004), twice a year, leads to well over 1 millions CDs being shipped quite easily.

Now assuming a "CDership" of 1.5, it makes the number of users who used Ubuntu via the ShipIt program is quite possiblly as high as 10 million.

That means that 0.001% of the worlds total population have likely touched Ubuntu in this way.