Ben wrote about the announcement that DC is going forward with an ambitious slate of prequels to Watchmen. Alan Moore and fandom at large collectively dug graves just so they could spin in them. Like Ben, I've thought about it quite a bit and here's my thoughts.
First things first: it's a money grab. The scale of the project speaks to that. The reason it's happening now, and not a few years ago when the movie hit and something like this would have made sense (from a purely marketing point of view) is that the comic book industry has reached its financial and creative end. A great deal was made of DC's decision just a few months ago to completely scrap its line and relaunch with a digital slate; the underlying thinking there was that the print aspect of the comics industry is in free fall. Print in general is, and comic books are not the only victims.
I see Before Watchmen as a last ditch attempt to both breathe life into and draw life from the creative apex of an essential American art form.
That's entirely separate from whether it's a good idea or not. We'll have to wait and see, but I don't believe there is anything to be achieved via this world or those characters that hasn't been already. Watchmen speaks to such a specific moment - the kill shot death of the form's innocence about itself - that to go back on it now says all you need to know about the form's artistic vitality.
I don't believe though that DC, or the creators involved, have no right to do this. Contract issues aside (Alan Moore's suffrage here has had generational benefits for those who came later), DC owns the characters and is free to do as they wish. Alan Moore has made a living in recent years off his co-opting of existing characters in The League Of Extraordinary Gentlemen (the Watchmen began life as characters from Charlton Comics). Though the characters of LoEG exist in the public domain, it's important to consider that most of the reaction I have seen from fans in general centers on Alan Moore's relationship to the characters more in spirit than in anything proprietary. It could be said Moore is violating his own argument in what he does with other people's characters.
Someday, regardless of whether he wants them to or not, people will freely make use of the Watchmen as they see fit. That they will doesn't diminish the characters or one of the great works of art of the 20th century; it only elevates it.