In 1993, Mel Croucher designed the first global member-get-member campaign using trackable routines embedded in product placement software. He also coined the word 'adware' and built a company around it. The technique became known as viral marketing, or buzz marketing, or guerrilla marketing. 'It seemed like a good idea at the time', Mel said in a BBC interview, 'but so did splitting the atom. Sorry.' For any pedants out there, the original campaign cost a quarter of a million dollars and sucked in 100,000 sales leads, generating a huge profit for Mel's client.

These days we do things a bit differently. We know exactly how to close-target your audience, and we know how to tickle their fancy with aplomb.