I heard that eBay sellers want to reply to bidder’s question without signing in to multiple eBay accounts many times. So I implemented this feature on the eBay listing software which is currently under development.
The “messages” link is shown on the left side navigation. When you click this, the items which have unanswered questions will be listed. Then you can reply to the questions for each item.
Below is just my development note. This feature uses following eBay api calls.