Gameinformer posted an interview with Junichi Masuda and talked about the Pokémon game franchise as well as the upcoming games Pokémon Black 2 and White 2. He also discusses why they haven't worked on a Pokémon MMORPG. Below is an except from the interview by Kyle Hilliard of Gameinformer. We have archived the full interview on our site as well.

How often do you hear requests from fans or the press about the possibility of a Pokémon MMO?
In terms of how often we get asked, I’m on Twitter and I get asked every once in a while, but it’s really not very often – from fans at least. I get the feeling that maybe not all of our fans are really interested in such an online game. It’s more so in interviews with the media and whatnot that I get asked about online games, like “Are you guys going to make an online version of Pokémon?” In terms of that, when you are playing remotely with someone very far away, obviously online, using the Internet like that is a really great option and it works great for that purpose, but with the Pokémon games, we really like to focus on face-to-face communication, and in-person communication, playing with people in the same space. One example might be like people from around the world come to the Olympics and have this huge event and that’s really exciting. While online play is a feature we also like and want to have in the games, encouraging this in-person face-to-face communication is something we want to continue to promote in our games.

Source: http://www.gameinformer.com/b/features/archive/2012/09/17/gamefreak-talks-pok-233-mon-s-first-numbered-sequel.aspx