The growth in the number of internet users is slowing down, far too early in the adoption cycle.

Comparing internet adoption with another fast-growing global technology, mobile cellular service, we see remarkably similar decreases in annual growth rates, from over 70% in 1996 to under 10% in 2015. However, mobile cellular service is nearing saturation at almost 100% penetration, while internet usage has not yet reached 50% of the global population.

Source: International Telecommunications Union (2015* numbers estimated), World Bank, Internet Society analysis.

The slowdown in growth rates is not just bad news, it is also puzzling, because the internet is more widely available and affordable than ever.

Take Rwanda – a country that has put the digital agenda at the center of its policy plans, with great success. Today 85% of the population is covered by 3G mobile broadband, and almost 40% have access to 4G. The Alliance for Affordable Internet (A4AI) ranks Rwanda first among developing countries on its affordability index. Yet just under 25% of the population subscribe to mobile broadband.

This shows that the digital divide cannot be filled with a “build it and they will come” approach. Instead, the question that needs to be answered is why are those who could connect to the internet not doing so?

The answer, according to survey after survey of non-users, as noted in a recent study on Brazil, is a lack of interest or perceived need for the internet. This, in turn, suggests that the missing element in bridging the digital divide is locally relevant content, which is in the local language(s) and relevant to local demand.

Source: Internet Society

Filling this gap may be as challenging, or more, than the efforts to deploy infrastructure. For instance, according to recent numbers, more than 50% of web pages are in English, while over 25% of internet users speak English, but only about 5% of the global population are native English speakers.

And even where language is not an issue, local relevance is key. While much existing content has international appeal, much is also targeted. A local online newspaper in Spain may not be of any interest in Mexico, French e-government services are of little use in Senegal, and Uber is only of interest in cities where Uber operates.

A key source of local content is local developers, who know the market and can identify needs. And while the internet provides fertile ground for entrepreneurs, putting access to education, training, cloud computing, and even fundraising potentially just a few clicks away, online innovation requires Internet access and skills, access to payment platforms, and increasingly local hosting solutions.

Focusing on local content generates a new set of challenges, and nurturing innovation is not easy. Without it, however, internet growth may continue to slow, and recent advances in access may not be fully utilized, which makes the access demand side the key issue for stakeholders trying to ensure that slowing growth does not become the new normal.