DuckDuckGo has launched a new feature called Cloud Save for anonymously saving search preferences that can be shared between computers.

There are no user accounts needed to be created. You just have to enter a long passphrase which is used for the saving of settings.

DDG spoke about the feature:

Your passphrase is used to generate a key using the Secure Hash Algorithm known as SHA-2, using a 512 bit key. Your passphrase never leaves the browser, only the key and the settings file associated with it. We save the settings file on Amazon S3 using the generated key as the name. In the interest of transparency, this data is not encrypted: you can see exactly what information we store.

Passphrases cannot feasibly be reverse engineered from a key
Even if you could do that, there is no point since all the information is there in the open, unencrypted, provided you know the key.
DuckDuckGo does not ever know your passphrase.

DDG’s primary selling point is privacy and this new feature showcases how serious they are about it.