God bless Tom Brevoort for having the guts to just come out and say it:
I cannot stomach the current fannish tendency to refer to the mainstream Marvel universe as “616.” It bugs me, in a sort of dopey, excusionary way… [R]eferring to the main Marvel Earth as 616 is counter-intuitive to the principles underlying the Marvel Universe as a whole–specifically, that while it’s a world of fantasy, there’s still enough of a semblance of verisimilitude that allows the average reader to relate these stories and events in a meaningful way to their own lives and conflicts and struggles. Marvel’s Earth is meant to be the “real world” far more than any fantasy construct. I have no problem with Alan’s use in his original stories, but thereafter calling it Earth 616 makes it feel all the more like a place of make-believe, of science fiction, of unreality. Which is it, of course, but acknowledging that in this direct a way shatters the illusion a bit too much for my tastes.
I also think it’s exclusionary. It’s the sort of term that means absolutely nothing to any reader who isn’t dyed-in-the-wool–even long-time readers don’t know where the tag comes from or what it signifies. And so the hardcore readers started to toss it around as a badge of honor, as a codeword that allowed them to identify one another. And from there, it simply began to grow.
More in the link, but I really don’t like the “616″ thing either, so Tom kicks the ass of rock for this one.