No matter where you go these days, you see people looking down at the small screen of a smartphone, whether that is an iPhone, Blackberry, Droid or other mobile device. It’s hard to overstate how quickly smartphone use is growing, both in the United States and worldwide.

A lot of these smartphone users are frustrated, though, because they are trying to navigate sites that were built with desktop and laptop computers in mind. It doesn’t have to be that way at your business. With a little forethought and work, you can tap this fast-growing marketplace, please customers and set yourself apart from the competition.

Just how quickly is this rollout taking place?

A study last month by the tech researchers at Gartner Group found that smartphone sales increased 72 percent last year, and an earlier study by Nielson predicts that smartphones will overtake ordinary mobile phones in popularity by the end of 2011.

The handheld computer market has developed so fast that many businesses are just now beginning to understand how important smartphones have become to the public, as a primary gateway to information. As a result, there are a lot of misconceptions out there about what the trend means for website owners and users.

Most significantly, companies often assume that their existing websites will translate just fine to this new reality. What that means on the ground, though, is that individuals interested a particular company will grow annoyed when they visit the firm’s site, as they try to navigate through a huge amount of information on a little screen.

By contrast, mobile sites are designed with palm-sized computers in mind. Smartphones recognize mobile websites and load those sites automatically. These websites improve the users’ experience and reduce the bounce rate of people immediately leaving your site.

Here are some things to keep in mind, as you think about how to make your site useful to people who are on the go:

Designers of a mobile website should not try to use all of the copy from a company’s full website. Instead, they should focus on the really important information that you want your visitors to know about you — phone number, directions, key services, etc. In a way, a mobile website is a “CliffsNotes” version of your business, conveying your message as quickly and effectively as possible.

Content management systems can create a direct link between a traditional website and its mobile cousin. This service can allow you to manage the content of both sites simultaneously.

Mobile websites should be functional for those scrolling with their index finger on a small screen, attractive to the eye and in line with the company brand.

Since this is a fast-changing, fast-growing area of technology, make sure that you talk with potential partners about their expertise and experience in designing mobile websites and about their ability to integrate it with the existing site.

Most businesses still don’t have a mobile website, so launching one can be a real differentiator in the marketplace. When you have a mobile website, you stand out from the competition. You show that your firm stays current and cares about the needs of customers and other stakeholders.

There also are some very good business reasons for making a company accessible to mobile users. Smartphones are becoming vital to your company, for everything from a supplier who needs to reach you immediately to a customer who wants to buy something right now.

For starters, smartphones allow customers to make a connection with you when they are physically in the neighborhood. Think about what that might mean for a restaurant or a store near the user, compared to a competitor who has not “mobilized” their website.

Also, smartphones are a kind of megaphone for word-of-mouth marketing, as users post their experiences on Facebook or Twitter; publicize their current location on sites such as foursquare; or critique the business through one of the many applications that now help people share their experiences through reviews of companies.

All in all, businesses can’t afford to sit out the smartphone revolution.

Today, having a good mobile website is becoming as important as having an attractive storefront window display and an engaging traditional website.