1Password is an original software to develop an unlimited number of passwords, grouped under the protection of one. The principle is the same as the ring, much to the difference of integration with browsers, and management of multiple identities. What the keychain does not allow you .
1Password is a separate application. We must set a password (different from the session), and then we can create as many passwords not that memorable sites.
1Password will thus create a 2nd ring, encrypted, located in the keychain file from your library, which will allow synchronization and backup at the same time as the main bunch.
Each form is linked to a URL. It may well have multiple forms per page (for example, to use webmail when you have several mail boxes).
It is thus an anti-phishing tool, because if you're on a fake site, 1Password does not issue you a form.