I have a professional forum, and a lot of visitors try ask their questions in private messages to me, not in a public topic.
If a visitor is not a paying customer, I have no motivation to solve his/her problems in private messages, but in some cases can do so in a public topic, because it could be a useful content for other visitors.
So an ability to move a private topic a public category would be great.
I see a request for the reverse feature: Flag option “convert into PM”, and it is also very useful for a professional forum.
I see also a partial solution (which is originally for the reverse case, but it works in the both directions): create a new public topic, then select and move all the messages from the current private topic.
It solves the problem only partially because I have to create a new topic with a some non-sense topmost post (there is no ability to create a topic without a post), and the new topic will have another author (the original author’s question will only be the second message in the new post).
There is also another partial solution: make a non-sense answer in the private topic, then select all the topic’s posts without the latest and move it to a new topic (the ability to move posts to a new topic is available only if not all topic’s posts are selected).
A good solution would be an ability to just specify a public category for a private topic, as we have in the public topic editing scenario.