Westeros Blog: GRRM on the Script

[Westeros]

In the course of a pre-C2E2 update, George R.R. Martin indicates that he had an excellent day of work, half of it spent on the book and half on the script for episode 8 of HBO’s Game of Thrones, something he says he never does, but it happened to work well.

He hopes for more days such as this, and will be back from Chicago on Tuesday.

He adds a final postscript: “Soon.” We leave the interpretation of this up to our readers.

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[Halfhand]

I think it is pretty clear that the final "Soon" is just a continuation of his previous thought. Alternately, it could be read as "Need to have more days like today soon." Basically him hoping that the next few weeks are productive writing wise. I really don't think it has anything to do with an impending announcement.

[Ser Mos]

Like you said, its most likely a thought continuation from "Need more days like today". It then occurred to him that more days like today don't help much if they don't arrive for another year or 2. So he added the "Soon" bit. It also suggests that there is a deadline (or 2) that he is aiming to meet in the near future. I don't think its much of a stretch to guess they'd be deadlines (self-imposed or otherwise) for ADWD and the ep8 script.