Found this in Rein's thread.

Quote Originally Posted by Reinheart View Post
This is in regards to feature letting the player know their item was sold.

Quote Originally Posted by Triairy View Post
こんばんは。
上記機能は、2回に分けてβテスト期間中での実装を予定しています。
Good evening,
For above metioned features, we are planning to implement in beta test in two separate phases.

βテストフェーズ1:売れたことを知らせるアラート機能
Beta test phase 1 : Alert feature letting you know your item being sold.
βテストフェーズ3頃:売れたアイテムの履歴確認機能
Beta test phase 3 : Feature to be able to check the history of the items sold.



アラート機能は、商品が売れた際にログインをしていると専用の音が鳴り、
売れたことを知らせてくれる機能です。
履歴確認機能は、進捗があり次第改めてご報告します
For alert feature, this one is a feature where it will make a sound once your item is sold and if you're logged in.
We will let you know any updates we get for the history check feature.
Doesn't say anything about what if you're not logged in while the item was sold. I'm assuming like other MMO's it will make the alert sound once you log in but no confirmation from reps yet. (plz talk on another thread, thx)
I wonder if they will ad a feature to provide a notification when logged out via email, sms, or some other method. It will be nice to be notified in-game at any rate.