Content creators (and press, like yours truly) often gain early access to games coming out in the near future, or announcements scheduled to be made.
NDAs are typically for repeated access to alphas or betas, where media are invited to test a game out and give feedback, but also can be used for more immediate coverage of an upcoming game or announcement.
The ramifications of breaking NDAs are quite serious — at best, content creators and media that break NDAs simply lose access to future coverage, and at worst, can be sued by companies for breaking embargo dates.