If the circus is coming to town and you paint a sign saying, “Circus is coming to Fairgrounds Sunday,” that’s Advertising.
If you put the sign on the back of an elephant and walk him through town, that’s a Promotion.
If the elephant walks through the Mayor’s flower bed, that’s Publicity.
If you can get the Mayor to laugh about it, that’s Public Relations.
And, if you planned the whole thing, that’s Marketing!