There are a lot of articles about differences between Transactional e-mail and Marketing e-mails (or bulk e-mails). I understand the business difference between these two, but is there any real technical difference between these two types of e-mails? I've been reading RFCs (like RFC 821 and RFC5321) but they not seem to be defining any difference between different mail types.
So is this just marketing bulls__t or are there actually any real technical differences between transactional e-mail and bulk / marketing e-mails?