I can't say this pleases me at all. Not one little bit
If Opera does become Flopera - I'll be jumping ship too which is a damn shame since Opera's continual extension improvement (and improvement overall as a browser) has been rendering FF more and more redundant to me personally.
I've never been able to find any love for Chrome, IE or Safari (or variants of those). It's always been FF or Opera for me. Over time, Opera slowly and systematically finally knocked FF off as my favourite/regular browser.
If it does go ahead - I hope they offer a 'regular' non-FB version alongside a FB one. I'm not against a Facebook orientated browser - it sounds great for those who are heavy facebook users; but not at the expense of my favourite.
Another downside is that it could potentially become one hell of a malware target.
I guess we'll all have to wait and see how this pans out...