Few things have made me more livid than what we've just learned through the answer given by AMtwo.
The data dump is one of the main reasons why I'm still participating to this day and has been part of the core values of this community. Please restore it, or consult with us to establish some equivalent way to protect and export our contributions as a whole.
I would like this bring the following pieces of history to the foreground. This is an excerpt of Joel Spolsky speaking on the Stack Overflow podcast #84
Oh, expropriation of community content that... We created Stack Overflow to be against it. If there's anything that's more in the DNA of Stack Overflow than that, I don't know what it is. That's one of our most core things. You can see this all over the place in the design of Stack Overflow.
First of all, from day one, we use the CC wiki license. And it's basically a license, it says that we don't own the content that's on there, which is why we make those database dumps that are available. Because we wanted to make sure that if no matter what happens, literally no matter who we sell to, or raise money from, or turn the site over to, and even if they take Stack Overflow, and make it an evil site where you have to pay to look at things and there's pop-up ads and pop-under ads, and you know, dancing, chariots of fire that cross the screen and punch the monkey, and, man, I can take so many evil things anyway. And it just becomes a big gigantic spam site.
Doesn't matter because just take the latest cc-wiki download that we provided and go start your own site saying, you know what, this is gonna be the clean version. And I think a lot of people will follow you. So the, you know, we very, very deliberately built Stack Overflow in a way that there wouldn't be any chance of locking and we're pretty much doing the same thing with Stack Exchange.
Also, on the blog, written by Jeff Atwood in 2009:
The community has selflessly provided all this content in the spirit of sharing and helping each other. In that very same spirit, we are happy to return the favor by providing a database dump of public data.