I think you're misleading in quoting a two-year old blog, then closing off with "ooops", implying that Mozilla was caught in a privacy-related oops.
When in fact, Mozilla was super duper clear in the blog about the privacy implications of this experiment. And in the past two years, they have been focusing more and more on the privacy angle.
At the moment, both Safari and Mozilla look to me to be leading in privacy.
Being super duper clear about having sent the full URL history of users to a third party doesn't excuse you from the fact that you, well, sent the full URL history of users to a third party.
And unless the entire leadership of the Mozilla Corporation has been replaced since then (a wet dream of mine) that blog entry is relevant, since they've done it and they could do it again.
Are you saying that nothing could ever excuse that fact?
Cliqz is building a European, independent privacy-oriented search engine. This seems a worthy reason to me, especially with the complete and total transparency here. And in any case, the experiment has ended.
I still maintain your comments are misleading, by leaving out the context.
Setting aside whether Cliqz could be trusted or not, just think of it: this is a decision that went through lots of managers in the Mozilla Corporation, and nobody ever stopped to think for a moment "sending the entire URL history of our users to a third party? well this is wrong". This is the kind of decision that should've led to lots of resignations inside the company, but nothing happened. To me this means there's something deeply rotten inside Mozilla. What kind of assurance do I have that they won't pull this off again in the future? And let's remember that they are strapped for cash, so it's not like they don't have an incentive to sell private user data again.