All of the affected pages have since been removed, and the Wurm team is currently deciding on a PHP-free solution for its web presence going forward. The news blurb on the temporary front page says that the decision will likely come next week. In the meantime, fans can keep up with developer happenings via Tumblr and the MMORPG.com forums.
Wurm is an open-world sandbox MMO that was developed in Java. It originally launched in 2006.
[Thanks to Bob for the tip!]