As far as I can tell, this is the correct URL:
http://k3b.org

So can anyone explain what happened to K3b's official website?

You find the homepage of k3b at k3b.kde.org

lueck wrote:You find the homepage of k3b at k3b.kde.org

Thank you for the reply, it's good to see that k3b still has an official website online.

But do you know why k3b.org does not redirect to k3b.kde.org?

I ask because a simple URL redirect would be very helpful for people unaware of the URL change.

Ademos wrote:But do you know why k3b.org does not redirect to k3b.kde.org?

No, please ask on #k3b on Freenode or mailto k3b@kde.org