It seems Valve is pushing for Steam to become more unified with the latest discovery by PCGamer that the digital-store is now offering to manage your monthly MMO subscriptions for you.

Currently the only title to offer this service is Darkfall Unholy Wars, a new hardcore PVP-focused MMO developed by Adventurine. Hopefully though this won't be the only title to support the option, as Steam holds a number of subscription-based MMOs including EVE Online and Lord of the Rings Online.

PCGamer reports that the subscription service does not currently support freezing, instead you will have to cancel and then renew later on. It also does not let you gift subscriptions, nor allow you to manage more than subscription per game, per Steam account. For a full run-down you can find the FAQ available here.