Some people seemed positively shocked by a new study showing that roughly two in five Americans don’t use the Internet.

The study, by the Pew Internet & American Life Project, found that 42 percent of Americans say they don’t use the Internet for anything — shopping, banking, research, e-mail or any of the other myriad things the Net is good for.

At first blush, it does sound a little strange that so many Americans haven’t found a reason to go online, despite all of the publicity, the availability and the falling prices associated with Internet use.

But on closer inspection, the numbers shouldn’t be all that surprising. Indeed, by historical measures, it’s astounding that Internet usage has become so widely adopted so quickly.

First, even though 42 percent say they don’t use the Internet, at least some of those people have developed strategies for using it without actually having to go online.

Fully a fifth of those who don’t go online have somebody else do it for them. They ask family members, for example, to send an e-mail for them or to look up information. That’s a nice deal if you can get it. Just like having your own research assistant.

Another 17 percent of nonusers are former Internet users who gave it up for one reason or another. Some had technical difficulties, such as computer problems or trouble with their Internet access provider.

Here again, no surprise. I’ve been tempted to cut the Internet cord and throw away the PC myself on more than one occasion when frustration was high. Those who tried PCs even five years ago may feel they didn’t deserve all the hype.

PCs and the Internet have improved greatly in recent years, however. So it’s quite possible that many of these “Net dropouts” will give it another try and one day return to their former status as Internet users. The Pew center found that only about half of nonusers say they have no plans to go online in the future.

The study also found that age may be the biggest barrier to Internet use, bigger perhaps than even lack of education or economic resources. Half of all nonusers are over 50, leading Pew to speak of a “gray gap.”

Nicholas Negroponte, the head of the Media Lab at the Massachusetts Institute of Technology, used to refer to the same group as the “digital homeless.”

In many cases, these folks are busy with work and family. Because they’ve survived and often succeeded without using the Internet, they see no need to take up the habit.

That may change for many of them after retirement, when they have more time and, perhaps, more disposable income after the kids leave home.

But here’s the remarkable flip side of the Pew center’s report. It was in 1993 that the National Center for Supercomputing Applications released Mosaic, the first popular Web browser.

That a mere 10 years later roughly 60 percent of Americans use the Internet regularly is the most shocking finding of all.