NYCC Announces Series Of Citywide Events Constructed Around Their Standard Convention Weekend
Here. Despite the hype right there on the front page of that site, NYCC is certainly not the first show to have events expanded out on one side or another of a core convention -- there's a show using that model that's going on right now. Toronto's TCAF this year also expanded back an indeterminate number of days (depending on how you want to count what's official and what isn't) and that was comics events rather than pop culture ones.
It's a good idea for NYCC in particular, though. Certainly it's something that most shows with the capability of doing so will do, and given NYCC's success and that show's status within the company it makes sense that they'd commit to something like that sooner rather than later. One thing that makes this a natural for New York is that so much of their exhibitor base and audience base is local, so it's not like you can't have a week's worth of programming and not have people to fill those slots.