If they are scammers they can be clearly downvoted or banned from the hive.
But it is sometimes difficult to decide what is valuable or not. I, personally, often prefer readings on professional sites and blogs. Readings on Steem are mostly good only about - Steem related topics... I sometimes read interesting posts here about investing, or see some nice photos. But with every good posts 3-6 bad ones appear. Professional sites have a better quality, are structured, redacted better.