Ah, if you can unsubscribe with one click, maybe even without logging in. What stops evil Bert over there from unsubscribing you? Sure, there might be some (session) token involved, but that could have been sniffed or brute-forced.
Actually mailing lists do it right, have the subscriber confirm his action by clicking a link in a confirmation mail or such. I think that's called double confirmation.
Pointless rant by some math student, or some programmer who feels he is missing out on math. Unclear on demands, probably wants to teach more math to kids.
I understand Canonicals intentions: with everything going "cloud" and "online" it makes total sense to offer just one search box instead of two. It's easy, it's convenient.
However it sends your input to a third party or maybe parties in the future. You no longer control your data. Is it even encrypted? Who can see what you are searching? Your family, your provider, everybody on your wifi?
It's not about ads in the first place, it's about data protection, trust and user interfaces.
However this isn't Ubunut, this is just Canonical Unity. I'd just install gnome-shell/kde/xfce/... and be done with it.
Maybe java security research just had a breakthrough and they found some new attack vector/methodology which uncovers all these vulnerabilites?