Still, even with a minimum of words per post, people who want to make money without spending too much time working will find a way to write posts that are only 200 words, and nothing more, so the spam won't go away.
I guess in the future the people at Steemit will have to think of a solution, because once this website will get over a few millions users, it's gonna be hard to find interesting content among the spam.
Anyway, thank you very much for your comment :)