TS and John Mayer ended their brief relationship Feb 2010. In his portion of the vid at Songwriters Hall of Fame Awards June 2010 he said [condensed]:
First of all she's ridiculously smart and present and aware. She's just got the germ, she's got the gene. Taylor is the world's biggest star who doesn't know she's a star. Taylor Swift is the last person to know she's Taylor Swift. I think it's nice for America to watch somebody appreciate. It's great to have someone who is hugely talented and still is able to receive the pleasure in all moments.
Every time I met somebody close to her in the industry, in publishing or management or a label, I would pull them aside and say Really, I won't tell anybody, I get this stuff, I'm on the inside too, who is writing those songs? Just tell me, it ends here and they would say she's writing those songs. And I would say OK I guess I can't chip away at you right now but I will find out who's writing those songs. And I asked her one night Honest to god, who is writing the songs? And she said I'm writing the songs. I didn't know where else to go with this; and we started playing guitars together one day and, sonovabitch, she writes her own songs.
She's not a product of a hype machine. Don't confuse a world of people loving one thing with hype. Sometimes that's just everybody agreeing that something is fabuious.
[Interviewer: Why did you decide to collaborate with her?] There's something about Taylor that she would've been a star in any decade and her voice is... I just thought in my little fantasy world if I was Tom Petty who would be Stevie Nicks? And it's like Taylor's this fresh voice and I don't normally make records to share tracks with people, I've never had someone else's name underneath the title of my song and I couldn't be happier that she's on there.