As of May 2013 the MMO market was observing a range of releases and announcements of games to come; of those that were available at the time the MMORPG official website ranked the top seven as they had observed them. The actual column written by William Murphy can be found here. While not all will likely agree with the rankings applied, each carries their own unique flavor to the industry and surprisingly are different enough in theme and content that any MMO gamer with ample time could easily make a week long schedule playing one each night and likely foster regular interest in each.
See the slideshow for images of each and details regarding some of what likely fed the fires of player interest in each achieving them that placement. Granted since this article's release there may have been a major shift in the popularity of any and all of these titles. Still it is definitely interesting to see knowing that when these games made their way to the public's eye most were typically either fantasy or science fiction based. The evolution of this gaming genre has managed to work its way into nearly every theme and the top games of May 2013 manages to reinforce that observation.
While the majority of the popular titles still maintain the fantasy or sci-fi themes; it is definitely a surprise to see such unique attributes of each title that they could easily forge a week long playing pattern with each game offering their own reasoning for interest. Though it is unlikely that many MMO gamers will venture across multiple titles on a regular rotation, the fact that there are titles, themes, and enough popularity to assure community within each; certainly makes little time for any that could try.