Are there any guidelines for posting appropriate content on Steem?

Hi people! I'm wondering - are there guidelines for what is considered appropriate content for Steemit?

For example, if I wanted to run a giveaway/promotion for an altcoin project - I'm not sure if this is considered appropriate or not. I'm not even sure that asking a question like this without it being full "blog post" is appropriate :)

If there are content guidelines for Steemit out there, I'd appreciate to know. Thank you!