From the Examiner:
The second major revelation was that the entire back catalogue of Dungeons & Dragons products would eventually be released in a digital format. Twitter fans noticed that they didn't say "PDF" only "electronic format." I confirmed this with the Wizards team afterwards -- they did NOT say PDFs, only a "electronic format" that's still in the works. So we'll see what form it takes. Of course, I've been predicting this outcome since the admitted goal of the new edition was to monetize the old editions, something WOTC can't do without actually selling the older editions.
I'm still sceptical about anything to do with WotC and the word digital. But releasing everything electronically is probably a step in the right direction. I say probably because the wording in the above quote leaves lots of wiggle room for insane corporate lawyer bullshit. 'Nuff said.