Fortunately, I never really used Crystal Keep.
See, I was thinking about what's happened, who this most affects, and that's what pisses me off the most. You and I and all the current 3E players that go on the internet to read/talk about it...we're already set. I used crystalkeep for reference tons, but mostly out of laziness from actually looking at the books/pdfs. It was convenient, but not essential. Further, we've had plenty of time to download those CK pdfs, and still can with the mirror sites that are up...until those also get taken down.
But anyone coming in new to the hobby? The books are gone, the legal pdfs are gone, CK's gone....all they have left is d20srd. No access to splat material for them. The core 3E game is wonderful, it hooked me. But I wonder how well it can hold up with just the vanilla core when 4E's plastering their new releases every single month. It's also going to make character building and optimization advice much harder to provide. I can't count the number of times I've linked people to CK to find useful items for their concept. No more. I doubt ENWorld will let us openly pass along the pdfs in the threads, since it's clearly now considered legally questionable to even view the things. Even if they had the frivolously large amounts of money to just buy a bunch of books for a few feats or items for a single character...WotC's also taken away that route. Again, we can't "advocate" piracy by telling them where they can obtain the rulebooks they want, either.
THAT is the chilling effect the cumulative efforts of WotC to bury the previous editions (next up: complete deletion of all the old web articles) that I'm worried and furious about. It's insidious, cold hearted, brilliant, and evil, and I hate them for it. It absolutely makes good business sense, I won't argue with that. They've decided they don't need our money, and after that stage, there's no point in trying to play nice for them. Even though it makes sense for them, I'm still going to rage and vent about it on teh interwebs.