A key issue with online channels for marketers is the 'digital divide' - the number of people who have yet to take the first step online and don't use the internet at all.
Just as the European Commission's Digital Agenda Scorecard has information on how many people in Europe go online for health, it also tracks the number of people who have never been online.
Here the figures show that across all 27 countries of the European Union just over 26 per cent of people have never used the internet.
This ranged at one end from Romania, where 57 per cent of people have never been online, to Sweden where the figure shrinks to just 7 per cent.
But these numbers have been consistently falling, with a drop of nearly 17 per cent between 2005 and 2010 in the number of people in the EU who had not been online.
So, while there are still huge numbers of people who do use the internet, it's important to know who you can't – yet – hope to directly reach online. (Though people who are not online probably know someone who is …)
• The EC's Digital Agenda unit has a series of useful interactive graphs on Europe's digital divide and more