And because of the Internet's word-of-mouth amplification powers, Mr Bezos cannot risk sending customers away grumbling.

ECONOMIST: Electronic commerce

For instance, even though the study found that the vast majority of brand conversations are happening offline, it also identified the internet as a crucial media component driving word of mouth brand advocacy.

FORBES: RIP Word of Mouth?

The concept: Create brand lust in youngsters by way of word of mouth (or Internet) among trendsetters.

FORBES: For the Discriminating Body-Piercer

Backed by primarily by some of her savings and one small investor, Ms Oliver launched Tribe Events in July last year, promoting the site through word of mouth and on internet search engine Google.

BBC: Annelie Oliver

That sense of family extends to their crew and their legion of fans, all of whom have discovered the band through word-of-mouth and, latterly, the Internet.

CNN: Hands up, I'm an Iron Maiden fan

The Internet, merchants are discovering, is a tremendous word-of-mouth amplifier.

ECONOMIST: Eventually, bigger means different

YouTube and the Internet have been doing this already, but music on Facebook will give the word-of-mouth phenomenon a huge leap forward.

FORBES: Will Music On Facebook Make Us Flightier Listeners?