If you take the definition that marketing is the process by which a product or service is made available to people and advertising is the active promotion of that product or service using (traditionally) paid for media then the differences should be fairly clear for all and sundry.
So why did we decide to confuse matters by naming some of the advertising tactics and channels available to us as ‘marketing’? E.g. Guerilla Marketing, Direct Marketing & Ambient Marketing.
Doing this has meant that people have misunderstood both, have misunderstood the role we play and value we bring to organisations.
If we want to change that, we’d better start being clear about how we communicate it.