No it's not spelled wrong, and it's not food. It's a new term creeping into the social networking community. Just as spam (also the name of a pork product) is unwanted and totally annoying, bacn is the new term for that new level of in between email. It's neither unwanted or wanted.
Bacn is the term for email that comes from your social networking site to tell you when you have a message, comment, blog post to read, or something else. Everytime your friends do something you can opt to receive bacn from them too. Before you know it your inbox is full of bacn.