Haven't all the major browsers had sync for ages? I've been using Firefox's built-in sync for so long I don't even remember what it was like without it.

Adblock, I would have thought. And Google can't compete in this space, by their very nature.

This is the message that Firefox needs to push: Hate ads? Use Firefox.

Considering that Firefox by itself doesn't block anything without extensions, that seemingly less than 10% of users use extensions and that tgere5are already quite a few snappier browsers that block ads by default...

Ooh, I think you're right. Even better if it can bypass more annoyances, cookie popups, captchas and (if legal) paywalls. Maybe it should have Libredirect built in. It could be a user agent, instead of a site owner agent.