This question is totally on-topic — it is directly linked to a tag which has hundreds of questions (domain-driven-design):
https://stackoverflow.com/questions/5612860/domaindrivendesign-org-where-has-it-gone
It has been closed as "off-topic" though.
An answer has been provided, but for sure, some people in the world could have a more precise answer (for example, when the reference web site will be re-opened).
EDIT 1 : There was indeed a more precise answer, it can be found here :
Where is the reference community web site about Domain-Driven Design ?
Anyone can copy my answer to the answer field, and I will accept it...
EDIT 2 : It looks like a few of you downvote this information, but many upvote it : https://stackoverflow.com/users/668455/tristan?tab=reputation#reppage_1-repview_post
I think this question should be re-opened, or the first one should be undeleted, re-opened, and answered.
I was only trying to correct all the duplicate wrong links in one shared place, instead of correcting them in many places. In programming language, this is called "factoring", and it's a good practice, as you may know.