Teledensity. Now there's a word.

According to TechEncyclopedia, teledensity is "the number of telephones in use for every 100 individuals living within an area." My neighbors, a family of five, have seven phones between them, not including phones at work and school. Tele-saturation, maybe?

We don't hear about teledensity in the US very often because we're a phone-rich country. Most of us struggle to pull away from the grid, whether it's email, Facebook, cell phones, Google. In developing countries, however, teledensity is a way for government agencies and international bodies to measure the digital divide. While One Laptop per Child was whipping the tech sector up with its rather adorable computer, organizations like the UN were taking a much more serious look at mobile phones, arguably the real workhorses closing the gap of the digital divide. In fact, in the UN's Millenium Development Goals, an initiative adopted in 2000, Goal 8f is to "develop a global partnership for development that would include making available the benefits of information and communication technologies." And the UN recognizes that many of the other goals: to eradicate poverty, achieve universal primary education, and combat epidemics are inextricably tied to the tools of information technology.

Measuring the number of worldwide cell phone subscribers is wrought with difficulties, but if the International Telecommunication Union is to be believed, we'll reach 4 billion mobile phone users by year's end. That's one in two people with a phone. All over the planet.

Anyone who owns a moderately decent cell phone can imagine the possibilities for a rural family with limited economic prospects. Fortunately, some innovate groups are not only imagining the possibilities, they're making them happen.

Two of the 2007 HASTAC/MacArthur Digital Media & Learning winners are using phones as a centerpiece of their projects. Mobile Movement (formerly Always with You) is currently in Nairobi to document a pre-selected group of youth entrepreneurs that will directly connect to business mentors through mobile phones in countries like the U.S. and Canada. No more third-party middle person handling correspondence, no more cash under the mattress - thanks to mobile phones.

According to Mobile Movement, "Young Kenyans can actually manage small businesses because of new technology that is accessible. And with Mobile Movement, you can build a history with a small business owner or youth group, build a relationship over time. And beyond individual giving, we are creating a trust-building system of micro-finance that could really change the way corporations and agencies like the World Bank and the UN help people in communities and monitor the progress of their smaller programs. It's going to be more possible to fund small groups and monitor them in a way that can really leverage a new style of funding, and could open up a lot of possibilities."

A similar dynamic is taking place with Mobile Immersive Learning for Literacy in Emerging Economies (MILLEE). Several months ago, MILLEE traveled to India for a field study.

As members of MILLEE explain, "The goal of this exploratory study was to identify opportunities for informal learning that e-learning games and other software applications on cellphones can facilitate. Out-of-school learning is especially critical in this context, for at least two reasons. Firstly, out-of-school learning can complement a public school system in which teachers are often absent or inadequately prepared to teach the official curriculum. Secondly, a substantial fraction of children in rural India who are school-going age do not attend school regularly because they need to work for the family in the agricultural fields or homes. As such, we envision that educational applications on a mobile device, such as a cellphone, can enhance access to education when employed as learning tools in out-of-school settings, such as the fields or home."

More often than not, I think of my phone as part nuisance, part convenience. Mobile Movement and MILLEE have changed that. Between e-learning and micro-finance, cell phones are stepping up to the world stage in a way that makes real change entirely possible.