If you are talking about musing.io then the answer is no.
If you are talking about question answering website then the answer is yes.
Musing.io is the first question answer website which is built on top of STEEM BLOCKCHAIN. And there is no website like this musing.io. As it is the first website built on steem blockchain, musing is all best till now on this session and hopefully it will remain so in future even if a new website come.
But if you are talking about only question answering website then there are many of them. The most popular question answering site is "Quora". There are many more like this such as ASKfm, Yahoo answer, Stack overflow, stack exchanger and many more.
Edit:
I think after the answer of me you edited. Yes there is many some website. But again the same stuff. those all are not like musing as they wont rewards you with vote(steem,sbd) but with other currency.
They have some rules an regulation which you have to follow while answering. below are the top 5 sites which pays for answering-
1- JustAnswer
2- Ether
3- Studypool
4- PrestoExperts
5- Experts 123
