One recent study estimated that 13 million social-media influencers generated $7 billion in revenues last year. The hottest platform of late has been fast-growing Instagram, which seems to have avoided much of the criticism that has so buffeted parent company Facebook. More than a year ago, Amazon also created its own influencer programme, a more exclusive version of its affiliate marketing system that is open only to high-end influencers on Twitter, Facebook, YouTube and Instagram. Participants get a custom store-front and vanity URL, choose products they want to spotlight, and receive a share of resulting sales revenue.

For a smart brand, getting its products in the right influencer stores can be a powerful opportunity to connect directly with that influencer's most devoted fans in a commerce-connected way that Google, Facebook, Twitter, and Instagram still can't match, at least not yet.

Some commentators are saying that the influencer programme has not changed much since its inception. However, it would appear that increasing numbers of people have recently signed up for the programme.