Do you know Chinese?
Baidu is a search engine in China.
It is the number one search in China which is one of about five or six markets that Google can't break into. It prbably works similar to any other search engine with the exception that most of the websites it indexes are in Chinese. So if you write in Chinese then you probably could SEO for it. It does index English sites but you have to realize that most of the people using this site don't care about English.
In the few instances that I've used Baidu I've found that the results are similar to Google just with Chinese sites included in the results.
In my personal use I find that Baidu is better at finding pictures, videos and music. The main reason for this is that if I search for a video on Google, half the time that video is hosted on Youtube which is blocked in China. With music, Biadu actually has a music streaming service.
If you are thinking of using SEO to show up in search results on Baidu, don't bother. Most of the people searching on Baidu wont be able to read your work.