The United States will close its digital divide significantly within the next four years, with 77% of U.S. households having a broadband Internet subscription, according to a new Gartner study.

Just over half of U.S. households currently subscribe to broadband Internet services, but Gartner predicts that that percentage will grow by more than 20 points by 2012. Amanda Sabia, a Gartner principal research analyst, says one of the biggest factors in the spread of broadband will be the advent of such 4G wireless services as WiMAX and Long Term Evolution that are expected to be launched in various markets over the next four years.

Worldwide, 17 countries will have broadband penetration rates of 60% or more by 2012, up from five countries in 2007, Gartner says. South Korea, which currently has the highest rate of broadband penetration in the world, at 93% of households, will retain its lead as the most-connected country in the world, with 97% of households having a broadband subscription.

With a projected 77% household penetration rate, the United States will be tied with Japan for the fifth-highest broadband-penetration rate in the world, trailing only South Korea (97%), the Netherlands (82%), Hong King (81%) and Canada (79%). "Depending on the specific market conditions, availability of Internet-enabled devices and the continued impact of broadband on consumer lifestyles, we expect some markets will have a broadband ceiling at 80% penetration or greater," Sabia says.

As broadband becomes more ubiquitous, ISPs will concentrate less on building out their networks to reach new customers and more on expanding what customers can do with their broadband Internet connections, Sabia says. In particular, ISPs will focus on delivering entertainment applications, such as Internet video content and games, as well as IPTV content and home networking applications, she says.

The digital divide between urban and rural areas in the United States has been a hot topic among both politicians and ISPs. Because many ISPs have stated consistently that there isn't enough money to be made that would justify expanding their broadband networks to large areas with low population density, many in government have suggested subsidizing rural broadband in the United States. A recent report issued by content-delivery-network provider Akamai Technologies found that significant disparities remain between urban and rural areas in broadband-connectivity delivery, despite a relatively high number of broadband connections nationwide.