A new term seems to have entered usage used to describe nuisance emails. Bacn is the term used for all those reminders, newsletters, notifications, limited offers, alerts and other ephemera sent by websites, e-tailers and other services you have used ever since you made your first mouse clicks on the web.
It takes its name 'bacn' because it tries to describe those messages that sit in the middle of a short continuum between which technical folks call spam (fake meat/junk mail) and ham (real meat/real mail). These messages are bacn because they are not quite real messages but are not quite junk either.
It is classed as a problem because it is something you probably want to read, yet not quite yet, and it masks the real email messages you want to read now.
The BBC web site has an article expanding upon the topic you might or might not want to read.