You could think of Steemit as a blog and social media site together in one place.
So you get the liberty to write whatever (long form or short form), on whatever topic interests you (that's the Blog part). Then you now get to interact with Steemians (our code name) as they comment on your posts (that's the social media part).
I'm way beyond my one sentence limit lol. Don't mind me, I love to talk. 😊
Welcome to Steemit!