Editor's Note:This is the first in a series of stories on mobile banking, looking at adoption, types of services, emerging technologies and how institutions are overcoming security concerns.

Mobile technology - it offers new opportunities for financial institutions to expand banking services and enhance the user experience.But the U.S. financial industry's adoption of mobile has been relatively slow.

Estimates for the number of U.S. banks and credit unions currently offering mobile banking-- via SMS/text, WAP/browser-based, downloadable applications or a "triple-play" combination of the three -- are hard to nail down. IDC Financial Insights in July reported that U.S. consumer adoption of mobile banking nearly doubled from 2008 to 2009, with SMS/text banking being the most popular. The (unspecified) number of institutions offering mobile banking also had increased, according to IDC, which based its data on a 2009 survey of 1,008 U.S. adults.