Musing is a decentralized application on the top of steem blockchain which offers a Q&A platform where one can ask question and others can respond to that question if they know about the question asked here. Both the type of users(asking question and asnwering questions) will be rewarded but there is a framework and/or guidelines of musing and based upon that it is curated by musing.
From your question, it feels like, you are interested to know posting guidelines of musing. So here it is.
Reference:- To know more details about musing guidelines, please follow this link
Thank you and Have a great day.
It depends on which musing you are referring to. Musing is a period of reflection for an individual and as for musing.io, it is from my understanding is a plug in to the steemit platform via steem connect where various questions are asked by random people and are equally answered as well.