Retailers have confirmed to ICv2 that at the Diamond Retailer Summit DC Comics announced that it would be running TV ads in support of its Before Watchmen launch as well as for the release of the first batch of hardcover collections of the “New 52” comics.  DC’s use of targeted TV ads to help launch the “New 52” was widely praised by retailers (see "DC's FAQ for the New 52, Part 2").
Given the fact that Watchmen has been a strong perennial seller in bookstores for years, and has a sterling literary reputation—it was the only graphic novel on Time Magazine’s list of the “Top 100 Novels” (see "'Watchmen' Makes Time's Top 100 Novels")—it has been read by a huge number of people who don’t regularly read comics.  TV ads appear to be among the best possible ways of reaching those potential customers and informing them about the Before Watchmen books.