Internet users of Hispanic background account for ten percent of Internet users. That represents 18.8 million people, and the proportion is expected to account for 24.4 million in 2011, according to a report by eMarketer Inc.

In relation to their overall presence in the US population, Hispanics are under represented on the Internet. Based on data from the US Census Bureau, Hispanics were 14.4 percent of the total US population in 2005, and will be 15.5 percent in 2010.

While they all have Spanish language in common, Hispanics are subdivided into many cultural and national groups, which makes targeting the Hispanic population difficult. People of Hispanic origin come from nearly two dozen countries, although nearly two thirds of Hispanic Americans are of Mexican origin.

"A defining characteristic of this segment is the variety of its nationalities, languages, degrees of acculturation, income and education levels," said Debra Aho Williamson, eMarketer senior analyst and author of the new report, "Hispanic Americans Online: A Fragmented Population."

"These factors yield a patchwork of Internet usage patterns," she noted. "The nearly 19 million Hispanic American Internet users do not constitute a homogeneous market. As important as it is, the choice between communicating in Spanish or English is just one piece of the puzzle," Williamson said.