In almost any other MMO, it would be a disastrous idea. You'd be opening up your precious lore to savage abuse by the idiot public. But comic books are resilient enough to take a bit of a battering. And if there's any set of comic book characters that's used to dealing with baffling and contradictory canon, it's superheroes. After all, DC had to create and destroy an infinite number of Earths before it could even work out what was going on in its own universe. Paragon City can probably deal with a few idiots like me writing stories about some bloke getting upset in a supermarket.