Europe is a diverse region comprising 48 countries, 27 of which are in the European Union. The region contains some of the world's Internet usage leaders, such as the Netherlands and Scandinavia, where penetration is around 80% of the population.

In contrast, countries such as Greece, Russia, Poland and Italy lag well behind the European average. But most of these nations are enjoying a surge of Internet growth. Within five years, only Russia will have less than half of its population online.

In terms of sheer size, Germany is the largest Internet market in Europe, followed by Russia and the UK, according to eMarketer’s recent estimates.

But “Internet users” means different things to different research firms.

Eurostat, the statistical office of the European Communities, measures Internet users ages 16 to 74. comScore measures Internet users ages 15 and older, while eMarketer measures Internet penetration based on the total population using the Internet at least once per month.

Much of the discrepancy in the following comparative estimate chart is due to these different definitions.

Russia’s Internet population grew 23% between 2006 and 2007, the highest growth rate among the measured countries, according to comScore World Metrix. Spain, Ireland and France also recorded double-digit growth -- well above the regional average.

The correlation between Internet usage and age is strong throughout the world, and Europe is no exception.

Data from Eurostat shows that 80% to 90% of 16-to-24-year-olds are weekly Internet users in most countries in Europe. Some of the notable exceptions to this high penetration rate are in the Czech Republic, Greece, Ireland, and Italy, which are all below the regional average.

But it is in the 55-to-74-year-old group where weekly Internet usage drops off markedly. Eurostat figures indicate that, overall, just 19% of European women in this age bracket were weekly Internet users during the first quarter of 2007, compared to 31% of European men.

Since this data was gathered, more senior Europeans have seen the benefits of Internet use and moving online. But the correlation between Internet usage and gender remains starkest in the 55 and older group. Estonia, and to a lesser extent Latvia, are the only two countries in Europe where there is a higher percentage of women regularly using the Internet than men.

eMarketer recently updated its Internet user estimates for 25 countries worldwide. These estimates and many others, are available to eMarketer subscribers.