Didio confirmed the shocking news in an ICv2 interview.
In what's probably the least shocking news of all time, Dan Didio confirmed that Pandora War will be a crossover event that will affect a decent portion of the New 52. In an interview with ICv2, Didio stated that he was looking to tighten up the continuity of the New 52 prior to an impending crossover event. He said that September's #0 issues will help tighten the continuity but that he was expecting the event to help boost the sales of low-selling titles.
Of course, DC used to be a big fan of crossover events, with Blackest Night and Infinite Crisis affecting much of DC's line during the "good ol' days" of the DCold. However, with the advent of the New 52, DC decided to lay off on the universe spanning crossovers and largely limited their crossovers to stories that spanned to one or two other issues. Night of the Owls, the recently finished Batman crossover, had been their biggest crossover to date and was limited to the 43 Bat-titles.
Marvel, on the other hand, has seen its sales rise in their Avengers vs. X-Men tie-ins, with most titles showing a significant jump in sales. While most of the tie-ins are mediocre at best (seriously, name one series not named Wolverine and the X-Men which hasn't been disappointing), Marvel recgonizes that there's a number of fans, nicknamed "sheep" by marketing expert, who will blindly flock toward a title as long as it has the latest event plastered on its cover.
DC, seeing the continued success of the tie-in, has no problem using shortsighted and unscrupulous tactics to boost sales. Before Watchmen is selling like hotcakes (personally I can't wait to see whether Rohrshach will survive!) and DC is always looking for new ways to make an easy buck. While its sales are significantly higher than last year and per issue sales are still greatly outpacing Marvel (remember Marvel's sales are also helped by double-shipping most of its' better-selling titles), it looks like DC is unable to simply try to boost sales by putting out good books and is instead reverting to the same tactics that caused the creative and sales stagnation that led to the company rebooting its line last year.