Spam volumes appear to have dropped to averages last seen in 2008. None of the vendors’ numbers showed the expected surge in spam over the Christmas period, traditionally a time when spammers boost their output. The fall is larger than the fall registered in late 2009, but still modest compared to the historic plunge that happened in late 2008 after rogue ISP McColo was shut down. It could also mark a change in tactics by spammers towards using channels other than conventional email, such as social media, to reach computer users.”]
Source: https://www.csoonline.com/article/2125949/sudden-spam-drop-leaves-experts-baffled.html