Honestly, I don't see what the fuss is about either with this one, but it's definitely making the rounds, and it happened "faster than a speeding bullet" as soon as the issue hit stands this week.
In the newly relaunched Action Comics #1 penned by Grant Morrison and illustrated by Rags Morales, Superman utters the words "GD" when he takes a hit from a tank missile. That was enough to send a retailer over at North Carolina, The Comic Conspiracy, on a campaign to boycott the issue, pulling it from his store. The story and reason behind this were reported in site Bleeding Cool, and here's the accompanying pic from the article.
in this story in BC, and the retailer finally got his answer from the writer himself, explaining the meaning behind the word. As how most people (myself included) know and have come to accept after reading the issue, the caption was supposed to emphasize a "grunt" like "UUMPH" or "DHH". DC's official blog The Source also published the story along with Morrison's answer to the supposed controversy. It looked like things could be put to rest from that point forward, but something new related to "GD" popped up just recently, courtesy of writer Mark Waid and his Twitter.
From an old Superman story in 1964. I guess the speculation and meaning behind the word will continue.