Duolingo are romantic saps. When Flavio asked them to help him do a a duolingo proposal, they did. See, Flavio knew that his girlfriend was taking Italian lessons with Duolingo so that she would be able to speak to her beau in Italian. He asked Duolingo to set up an exercise just for her that would lead to the big question. It began innocently enough, with "Lui ti ama" to translate. "He loves you". Then "Lui ti adora", he adores you.. and then it got personal: “Will you marry Flavio Esposito?”
Relax. Kate said yes. And with that Duolingo bought themselves a little internet-fame as people-who-love-public-proposals all over the world will be sharing this story, advertising Duolingo while they're at it. I'm not a big fan of the public proposal, its used to be you didn't need a choreographed routine with backing dancers and a film on youtube to do it, I am however a fan of the personalized proposal. This is a personalized one that became public as the company are (wisely) using it to show off how fab they are. And with that, it's also quite a neat ad for Duolingo: want to speak the language of love be it Italian or Spanish or whatever it is your love interest speaks? Check out Duolingo. They'll even help you propose.
Duolingo teaches you some rather odd, if sometimes useful, things to say in various languages. See shitduosays on twitter.