BioWare's Chris Priestly took to the BioWare Social Network to respond to speculation about the next installment in the Mass Effect series of shootery role-playing games (thanks Strategy Informer). In what seems evidence that the era of sequels is hitting a new era of oddness, he suggests calling the fourth installment in the Mass Effect series Mass Effect 4 or ME4 is a "disservice" to the game:

To call the next game Mass Effect 4 or ME4 is doing it a disservice and seems to cause a lot of confusion here. We have already said that the Commander Shepard trilogy is over and that the next game will not feature him/her. That is the only detail you have on the game. I see people saying "well, they'll have to pick a canon ending". No, because the game does not have to come after. Or before. Or off to the side. Or with characters you know. Or yaddayaddayadda. Wherever, whenever, whoever, etc will all be revealed years down the road when we actually start talking about it.

I do not call the game ME4 when I talk about it ever, bucause that makes people think of it more as "what happens after Mass Effect 3" rather than "what game happens next set in the Mass Effect Universe", which is far more accurate at this point. Obviously fans are going to speculate content, character and story until we actually reveal details in the years or months to come as you have almost no actual details, just don't get bogged down in "well how are they going to continue ME3...".