To get access to Africa’s burgeoning middle class, some of the world’s biggest multinationals are offering potential customers a special incentive -- free cellular airtime in return for filling out a survey or watching a video.

As a result, companies like Unilever, Google and Nestle as well as agencies like the United Nations are able to connect to a market once hard to reach due to infrastructure and connection problems. The tool was the brainchild of Nathan Eagle, an entrepreneurial Harvard epidemiologist and his supporting cast of Silicon Valley heavy hitters at Jana, a mobile advertising company that links brands directly to consumers through their text-message inbox.

While testing out SMS-based surveys in Kenya eight years ago, he realized that people would eventually stop responding because they weren’t willing to spend airtime on the extra messages, Eagle told the International Business Times. The vast majority of cell phone users in developing countries are on prepaid plans, which means every call and text takes a certain amount away from their total balance.

Eagle soon realized that mobiles could be useful not just for communication, but compensation, and found a way to send free airtime to participants’ mobile phones in exchange for completing the survey. It worked. And by 2009, he spun this idea into a business model for Jana.

A list of Jana’s board members reads like a who’s who of Silicon Valley and the advertising world:  Publicis Groupe Chairman and CEO Maurice Lévy, AOL’s CEO Jon Miller, tech venture capitalist Esther Dyson and Paul Sagan, CEO of Akamai are all involved.

The company reaches millions of people every day through 237 mobile-operator integrations. Clients include Procter & Gamble, Microsoft and Johnson & Johnson, and they’re all using different methods to reach their target markets.

In Indonesia, for example, customers who purchased Danone products at Carrefour stores received a scratch card with a code. After dialing the number underneath, they instantly receive 5,000 rupiah (about 44 cents) worth of airtime credit, and could make another 5,000 rupiah for referring three friends on Facebook. Sales of the targeted products increased by 27 percent.

On March 19th Jana launched their “Marketplace” platform that allows consumers choose from different ways to add extra credit to their mobile plan. Possibilities range from watching short videos or writing down a shampoo preference, all of which help the company’s clients.

And with the exponential growth of smartphone use and corporate demand for new markets, business is booming.

Besides helping companies sell products, the data can be used for development. Eagle also holds positions at Harvard and Boston’s Northeastern University and is part of a World Economic Forum committee dedicated to using big data to help solve big problems.

Though he works in dozens of developing regions, Africa is of special interest to him.

As lower-cost smartphones come on the market, more and more Africans are getting connected. For about $30 it’s now possible to buy a phone with GPS, Wi-Fi and a camera -- which means big things for Eagle’s research and Jana’s business.

“Suddenly these billions of people are all going to be getting online, and that’s really exciting,” he said, predicting that it will be nearly impossible to purchase a non-smartphone (or “dumbphone) by 2016.

This groundswell means more than just a greater number of eyes on global brands. The infrastructure can also be used for much more than advertising. “Some of our biggest clients on the survey front are the United Nations,” he said. Surveys sent to mobile phones can be used to get information about anything from a person’s current health status to their annual income, which has major implications for local policy makers.

Al Jazeera English also worked with Jana to help cover elections in Pakistan and India. Before the most recent pope was elected, CNN used Jana surveys to poll 20,000 people in sub-Saharan Africa.

The possibilities are endless. But for Eagle the ultimate beneficiaries are the participants, who can profit from the information they produce. In many of these regions, consumers typically spend between eight and 12 percent of their daily income on their phone plans.

“You don’t often get an opportunity in life to give a billion people a five percent raise.”