To be able to identify the traffic from your newsletters in the sources, you must first declare a marketing campaign in your interface under Settings> Settings > Marketing Campaigns > Emails:
After carefully selecting your site, click on "Add" to create a new campaign. Choose the type, start date (and possibly end date) and fill in the declaration field following the xtor.
To help you create the xtor parameter, do not hesitate to use our Campaign Creator tool. Please note that campaigns are taken into account 1 hour after their declaration.
You can then add the xtor parameter at the end of the links in your newsletter leading to your site, making sure to respect this format:
http://www.site.com/#xtor=...
or
http://www.site.com/index.php#xtor=...
or
http://www.site.com/index.php?other_variable=2#xtor=...
Once these steps have been completed, you will be able to see the traffic from your newsletters going up in your Explorer > Trafic Sources > Marketing Sources > Emailings interface.
To save you a lot of time-consuming declarations, AT Internet also offers AutoDeclaration, a free option to be activated.