I see this as a reaction to the competition they're facing with Google Chrome.<p>With Google Chrome you log into your Google account. email + password and all is good. It's <i>simple</i>, but fundamentally insecure. Google, NSA and whoever else they partner with can poke at all your data without restriction because it is based on a centralized authentication model.<p>Firefox always based its sync on a <i>secure</i> model where no data was stored unencrypted at Mozilla's sync-servers. There was no traditional "account" which Mozilla had to validate. You could also chose to use your own sync server. Either way, they can not peek at your data.<p>You gave Firefox your email and a "password" and from that it generated some private keys used to encrypt the data sent to Mozilla. Private keys which you then had to distribute to other Firefox'es one way or another.<p>They attempted to ease the pain by having some "pair this device" wizards with 3 simple values you could copy from device A to device B, but in the end it still meant that the superior security came at a cost.<p>No non-technical people I know use Firefox's sync, but everyone I know who use Chrome also use its sync feature.<p>When comparing browser, some people literally list out "sync" as thing Chrome does and Firefox doesn't. That tells you a lot about how a simple and in your face implementation can drive adaptation. (I think Chrome's approach is too in-your-face, but that's another discussion.)<p>I honestly believe Firefox's original model is superior once you get past the initial warts, but I can see why they are making the changes they do.