A surprising number of U.S. Internet companies still operate without a real mobile-first strategy, though nearly everyone thinks they have one. Whether they know it or not, their businesses are on a respirator, especially if they have any thoughts about growing outside the U.S.

Outside of the States, especially in emerging markets like Brazil and India, consumers aren’t shifting from desktop computers to mobile devices like we’ve seen in the U.S.

Instead, for many of these populations, mobile is the Internet, and often provides their first online experience.

I’m not the first to point this out, of course, yet, amazingly, many still don’t seem to get it. In these markets, desktops are an afterthought, because — unlike in the U.S. — hundreds of millions of consumers leapfrogged the PC era altogether, joining the connected world in earnest through their mobile phones.

“Mobile-first” is an often-empty term — like “viral,” “native” and “social” — that’s thrown around without much thought into what it really means. Mobile is a foundation, not a feature. It may hurt your wallet to even consider, but maybe your product should be reimagined for a mobile environment, not just adapted to fit a small screen.

Even Facebook still faces debate about whether it is truly — and finally — a mobile-first company. The answer is yes — not just because mobile ads now account for a majority of Facebook’s total ad revenue, but, more importantly, because the site’s mobile apps (plural) now offer a first-class user experience (not always the case) that rivals the accessibility of the desktop experience we’ve grown used to.

Facebook CEO Mark Zuckerberg has said, “If 2012 was the year where we turned our core product into a mobile product, then 2013 was the year where we turned our business into a mobile business.” You have to be just as inherently mobile as your consumers are. It’s amazing that this is still a topic of conversation in 2014, but yet …

Chinese Web giant Tencent (think what Facebook, Yahoo, Amazon and Zynga are collectively to the U.S.) has reached a whopping $100 billion valuation today because its management understands how to approach mobile — they get it. It’s no accident that Tencent has become China’s largest listed Internet company (by revenue) — it’s the direct result of the company’s exploitation of the country’s mobile opportunity. (Full disclosure: Tencent shares the same investor — Naspers — as OLX, which I co-founded and lead as CEO.)

Mobile requires a fundamentally different mindset, and a commitment of focus and resources, two things that not everyone is willing to expend in unproven Internet markets like the Middle East and South America. In India, Brazil and elsewhere, the company I founded recognized that rapid mobile adoption was changing the landscape entirely — so much so that it created an entirely new economy between consumers.

Doubling down on mobile early cleared the way for new, massive, consumer-to-consumer markets to develop on OLX’s service, as people learned that they can instantly sell goods and services from their phones. At the time, many might have thought the strategy was a gamble, at best, in undeveloped markets where mobile technology was still nascent. No one is saying that now, with our mobile traffic growing by more than 20 percent monthly in some markets.

In September, Zeng Ming, chief strategy officer of Alibaba (another Chinese e-commerce behemoth), told a reporter, “The fundamental assumption is that the mobile space could turn out to be 10 times bigger than the PC space.” Like the PC, Internet companies that refuse to accept this will be afterthoughts in emerging markets.

The antiquated strategy of building for PCs and making a serviceable mobile version is a recipe for failure in a mobile-first world.

If you approach the process this way, you’ve lost before you’ve even started. Consumers — from New York to New Delhi — have choices. If you don’t build the most fundamentally mobile option for consumers, you can be sure that someone else will.

Alec Oxenford is co-founder and CEO of OLX, a global online classifieds service. Reach him @alejandrito.

This article originally appeared on Recode.net.