The Cisco Talos and Umbrella research teams are deploying a distributed hailstorm detection system. Using such techniques, snowshoe spammers intend to fly under the radar with respect to any reputation or volume-based metrics that could be applied by anti-spam systems. The US, Germany, Netherlands, Great Britain and Russia lead the pack in terms of volume of spam sent by country. Most of the campaigns we initially detected advertise products such as home-surveillance systems, flashlights, dietary supplements and all sorts of items “as seen on TV””]
Source: https://blog.talosintelligence.com/2016/12/in-eye-of-hailstorm.html