Ok, here goes what I think: Gaga says it's the 1st installment, which means there will be at least one more. But, we know ARTPOP music is coming soon, which mean the album itself might take a few months to come but not very long. Therefore, the 2nd installment of the BTWBall might be until the end of 2013 or even longer. By that time, ARTPOP will for sure be out already. And I don't think ARTPOP will be out very long without having a tour for it but Gaga won't finish the BTWBall so soon. So, what I think is that ARTPOP will be an album with just a few songs, maybe like The Fame Monster. Gaga will learn choreographies for some of those songs and she'll make the 2nd installment of the tour with songs from BTW and ARTPOP. So, if the 1st installment of the tour ends in March 16th, ARTPOP might come out short after that. I know this is too much but I really believe this is what's going to happen. Let me know if you agree of if you think I'm crazy :3