In Grand Theft Auto: The Ballad of Gay Tony, an advert featured in Star Junction (the GTA equivalent of Times Square) appears to tease where the series is headed next. The ad, which is replicated in the Episodes from Liberty City instruction manual, declares "Liberty City, It's Over!" to signal that the GTA IV saga has ended. It then states "Next Stop," but the portion revealing the 'next' location has been torn away, exposing part of a previous advert.
The ad is a parody of the 2009 film New York, I Love You and there's been much debate in the GTA community over whether this is a genuine hint or simply a joke. The advert underneath (which is partly exposed) can be found in several places across Liberty City, and many believe this (if anything) is what holds the clue.