Why YSK: So you can easily and digitally write and share mathematics, for free.
I used it for 3 years during my bachelor for many different courses, and I was very satisfied from the variety of choices and outcomes.
Limited to 50 documents and total maximum images upload is 50MB (thanks @cloudless@feddit.uk)
Oh yeah! I remember using this once! It was good stuff.
I then moved over to LyX, and it was just a better experience. I liked not having to be connected to the internet to look at my math notes.
Cool that is new to me