A thread on the Steam Users' Forums discusses the disappearance of Dragon Age II from Steam. There is widespread speculation that this is due to the new Legacy DLC for BioWare's role-playing sequel being sold from within the game, a situation similar to the one that has lead to the removal of Battlefield 3 preorders from Steam for the same reason, as this is apparently a violation of Steam policy. Meanwhile, with the new DLC now available for 800 BioWare spacebux, here's a description of what it adds to the game:

Targeted by a vicious criminal cartel that are hunting "the blood of the Hawke," you must put an end to their relentless attacks. Leave Kirkwall, and journey to an ancient Grey Warden prison in order to find the source of the aggression and uncover the harsh truth about the Hawke lineage. Playable from any point in the Dragon Age II campaign, face new breeds of darkspawn, forge a powerful new weapon and come face to face with an ancient horror.

    • Uncover the harsh truth about the Hawke lineage
    • Adventure through several new locations including a prison constructed by the Grey Wardens
    • Obtain a powerful class-specific weapon to which you can apply upgrades of your choice