Bacn is email you want but not right now...Common examples of Bacn messages include news alerts, messages from social networking sites and wiki watch lists.
My inbox is full of messages from important but mostly uninteresting egroups and event reminders that are there only for redundancy reasons, to make sure things get through my oft-procrastinating skull (I also have Google Calendar open in a tab most of the time, plus I've turned on its SMS-forwarding feature). Then there are the electronic newsletters that I just might read some time in the future, but for now are labeled and archived out of view.
Just like spam, in practice bacn isn't limited to email. Birthday alerts on your cellphone, possibly interesting but non-pertinent entries in your RSS reader...heck, normal/paper newsletters, or even bills (if you're a lazy bum)...probably could be considered as greasy chunks of bacon...er, bacn.