43.1 million. That’s the number of people who are 65 and older in the U.S. right now, the largest this group has ever been. Demographers report this population segment will continue to grow rapidly, more than doubling by 2060. An aging boom like that impacts ecommerce, as evidenced in usability research by the Nielsen Norman Group (NNG).

According to NNG, 19 million American seniors were using the Internet in 2012, representing an increase of 16% each year over the past decade; by comparison, Internet users ages 30-49 grew at just 3% per year. These rates for new Internet users look similar in other developed countries.

As more people over the age of 64 turn to the Internet to satisfy their information and transactional needs, are websites ready to meet this population’s requirements for a good customer experience? NNG’s findings say no.

The consulting firm set up a two-phase usability study with 75 senior citizens (mostly Americans, but also participants from Australia, Germany, Japan, and the U.K.). In the first phase back in 2002, 44 participants tested 17 websites; in 2013, 31 participants tested 29 sites. On all tasks—success rate, time on task, and errors—participants’ performance improved fairly well between the two phases, but fell short against current users in the 21-55 age bracket. Considerably shorter. For example, seniors made twice the number of errors, and were 35% less likely to successfully complete their tasks.

According to NNG, there are clear disparities between seniors and younger users when it comes to vision, dexterity, and especially, memory. What does this mean for ecommerce websites? Obviously, they have to understand that while seniors might be getting better at doing things online, they haven’t grown up with technology and so don’t find it as intuitive as younger age groups. Their time on site is higher likely because they are getting lost as they navigate websites and struggling to get through checkout.

Websites that want to succeed should reduce the number of actions visitors in this group needs to take to complete a goal, use a bigger font size, and display simple navigation instead of throwing a whole jungle of buttons at them. And here are some specific ideas for how travel suppliers and retailer websites can better serve this valuable customer segment:

Travel Suppliers: Don’t interrupt the primary goal.

If a senior is purchasing a train ticket, hold the upsell offer until after you’ve confirmed purchase of the ticket. Wading through a page of hotel and excursion deals to figure out if the booking has gone through is confusing for seniors—and for visitors of all ages, for that matter. So save the add-on deals for later.

Keep in mind that seniors have more than double the chance of kicking an error back than younger visitors. And when these visitors run into problems online, NNG found, they tend to blame themselves. Help them build their confidence online by simplifying processes where possible. For example, strip away form validation for the less important fields to improve seniors’ rate of goal completion.

Retailers: Merchandising done right.

To be more useful and relevant to this segment, cater the merchandising on your website to their interests. For example, an online drugstore could better use its homepage real estate to promote products that fit a visitor’s implicit or explicit interests, as well as swap out promotions for mobile apps and other more tech-savvy options with content that advertises discount programs, instructive videos, and customer service information.

With the holidays coming up, retailers should also take advantage of a prime opportunity to help this customer segment simplify the gift-buying process. A toy retailer, for example, could steer seniors away from the feature-laden main site to a tailored landing page that provides a gift-buying guide (check out the example to the right).

The toys could be categorized by the most popular items for each children’s age group, so visitors don’t have to navigate through the entire online catalog of toys. A custom gift-buying guide is an idea that works for other product types too, making it easier for this customer segment to wrap up their holiday shopping.