Will phrase and PIN be the new username and password?

Amazon seems to think so. Last week the etail giant announced Amazon PayPhrase — a new payment method for users of its US site.

Users who have stored their credit card and shipping details on the site can link them to a unique phrase of two or more words totalling up to 100 characters. Rather than logging in with a username and password, a returning PayPhrase user can simply type in their unique phrase and a PIN to complete a transaction.

The service will also work on any other site that processes its transactions through Amazon Payment - the etailer’s rival to PayPal and Google Checkout - dispensing with the need to create new accounts on multiple sites and providing a consistent checkout experience across multiple etail sites.

Early reviews on the web have been mixed. Is remembering a phrase and number really simpler than logging into a site the conventional way? Or is Amazon laying the ground work for future methods of interacting with transactional websites?