You should really head over to the musing Discord server and spend some time there. I can attest that there are a group of people that manually curate the answers and vote on them. It has been pretty well covered over in the musing chat room.
They put a lot of time and effort into this for very little reward on their part. Instead they choose to give those rewards back to the people who are posting and answering questions. Since it is not an algorithm, it becomes pretty apparent to them who is posting answers that actually have value and who is just spamming the platform.
If you have been upvoted on here in the past you will notice that all upvotes come from the @musing account. That is the sole account that has been delegated the bulk of the SP. I am not sure the entire process the group follows for picking the answers that they are going to choose to upvote, but you can probably find out over on Discord.
I typically just try to do my best to answer as honestly and accurately as possible. They have a hard job and a lot of love to spread around to a lot of people so it is best to be patient and understanding with them.
Musing is a dApp built on steem blockchain. Hence, there are two options available with the musing to incentivise its users.
Programing the upvote is easiest way but it deteriorates quality of the content. In order to maintain quality, avoid spammers and avoid the abuse of the platform, Musing curators manually review the questions and answers and upvotes them manually
Musing is made on steem platform and it is been delegated with huge Steem power after getting his journey towards success. The upvotes you get is from the team itself. As per my research the team itself upvote our post, they are not running any algorithm behind upvotes.
The concept behind delegating is the steem platform itself or steem team who delegate best dapps made on steem platform. You can check steem press with huge Sp same like musing. So they pick the best dapps and delegate Sp to help their community. There might be some terms and conditions to get higher Steem power in delegation.