The number of ”graying and affluent” households is on the rise–and more and more of them are embracing the Internet as a shopping medium.

That’s the word from International Demographics, whose new Media Audit revealed that 65.6% of “graying and affluent” households had made at least one online purchase in the last 12 months–versus 50.2% the year before.

The Media Audit defines the graying and affluent market as those over the age of 50 with incomes of $50,000 or more–and they make up 15.7% of all the households in the US.

This certainly isn’t news for anyone who’s been following the social and economic impacts of the aging baby-boomer generation, but it may be a timely reminder for marketers who still think the Internet is only for targeting the Gen X and Y crowd.

Even if many of the older and wiser audience never go near the Internet, the fact remains that their children and grandchildren will.  As caregivers, they’ll use it to research and make decisions on behalf of their elders–on everything from finding a new doctor and purchasing a car to everyday things like filling a prescription or shopping for shoes.

So are the graying and affluent among your target audience? If so, take a step back and make sure you’re not ignoring their Internet savvy–or the Internet savvy of the ones who love them most.