Alan Keller loves it when people tell him their web sites are mobile-friendly. He immediately challenges them to pull their site up on a smartphone, and then watches, and usually waits, as the desktop-designed page loads slowly on their palm-sized device.

“Sure enough, it’s PC rendering but on an Android,” says the chief revenue officer of DudaMobile, a Palo Alto, Ca.-based mobile web design shop aimed at small businesses. “Think of all the content and images on your PC site. That’s not made for a small screen.”

Reps who haven’t upgraded their web sites for the mobile age are in danger of being the dinosaurs of the Internet, and it could lose your firm credibility and business. Increasingly web browsing happens on mobile devices. There were about 1.5 billion mobile phone subscribers globally at the end of 2012, according to the annual Internet Trends report from Kleiner Perkins Caufield & Byers partner Mary Meeker. That’s up 30 percent in one year alone.

Mobile users make up 15 percent of all Internet traffic, compared to 10 percent a year ago. With 71 percent of small business owners looking to increase their budgets for marketing over mobile devices, according to a recent AT&T survey, streamlining a web site for smartphones and tablets is crucial lest you lose that on-the-go investor.

To Keller, priority number one is making sure a site looks clear and visible on a mobile screen, with easy to see buttons where prospective clients can click to call an advisor or make an appointment. There should be a link to a mobile map so visitors can easily get directions to an office. On a web site, it’s common for people to scroll to the bottom of a screen to get to contact information. On a mobile site, that’s awkward.

“You want thumb-friendly buttons,” says Keller. “Fonts need to be easy to read, with a clean layout.”

Olivia Ballvé agrees that information needs to be easy to see, and load very quickly. The vice president of support and partnerships at the New York-based bMobilized encourages small business owners to either load up their web sites on their own phones, or use the firm’s free emulator to see first how fast the site comes up on a device. Desktop sites are optimized for much more bandwidth than phones, she says, meaning a site that loads in just two to three seconds on your Mac might take up to 15 seconds on your iPhone.

“So the first thing we’re doing is stripping down [the site] so it can load faster,” she says. “You lose 75 percent of your prospective customers if a site doesn’t load in five seconds or less.”

For financial advisors, a mobile-friendly site is crucial particularly with current clients referring friends. If a prospect pulls up the link on a phone at an afternoon barbecue or a weekend dinner party — a slow site is a lost opportunity. Igor Faletski, CEO of the Vancouver-based Mobify, which helps brands translate to a mobile environment, should know — his sister is an advisor.

To him, a mobile site should look and feel just like a mobile app. In particular, visitors don’t want to have to pinch or zoom into a screen to see information. Today, sites are best designed when they respond intuitively to the screen they are on — optimized for a PC, a tablet, a mini-tablet or a smartphone instantly. The best design is one that’s effortless to the user, believes Faletski.

“Consumers are biased against web sites that aren’t mobile friendly,” he says. “Businesses should think if they’re in the business of good service or not. And everyone in business should think they’re in the customer service business.”