Headlines are specific to the central theme of a piece, designed to resonate on an emotional level.
Headlines typically appear on web page banners, in value propositions, in brochures, advertisements or emails.
Probably the most famous headline is David Ogilvy's 1960’s masterpiece, “At 60 miles an hour, the loudest noise in this new Rolls-Royce comes from the electric clock.”
Copywriters invest a great deal of time writing headlines, sometimes as much as it takes to write 500 words of body copy.
A strapline is a long-term property, created to reflect the essence of a brand. Straplines are typically used in conjunction with corporate brands, but can also align with specific products.
Apple’s “Think different”, Nike’s “Just do it” and Nokia’s “Connecting people” are examples of effective straplines.
A tagline is the same as a strapline, but the term is used more in America.
Slogans are often former straplines that become so popular; they end up used in the broader community. “It does exactly what it says on the tin” is an excellent example of a former strapline that broke through into the more general vernacular.