Cristiano Ronaldo does it really obviously. He sticks his arm with the gaudy watch in front of the camera and can barely contain his enthusiasm in the caption. What a piece of work! Other stars and social media meteors try to use product placement to achieve the same goal with a little more discretion: Making brands familiar or friendly, inciting to purchase. In marketing jargon it’s called influencer marketing. People with something to say, or who have a lot of influence, become brand messengers by feeding advertising – that often doesn’t seem to be advertising – into their media channels. Celebrated as the new cure for small retail circles. And rightly so.