Setting
XMM is set primarily in New York, with some characters living in Westchester county, about an hour away from the city proper. We are set in present day time, but some factors are obviously AU. We have mutants, for example. Also, our President is currently Henry Richards, not George W. Bush, and mutant politics and issues are high on both the political and private radars. Events like Liberty Island, the assassination of President Lowe, and the 11/9 Purity Massacre live strong in the public memory and often affect roleplay. Check out the major events and history pages for information on big events in the game's history.
In general, we assume most pop-culture, economic, and natural events to occur on-game in realtime. We're a bit more careful with politics, as they are often directed by plots. We also assume our weather to be equivalent to New York's in real time, and checking out the current conditions can add an interesting twist to RP.