is steemit a scam ?

i feel i need to post this im not calling steemit i think that its a great idea infact i think it could be the future of social media.
but upon review the only benfical posts ive seen are from the people who are paid to promote this site say they made over $500 on there post but from what ive seen its not.
its seem more like you have to invest cash to make things move ?????
surely this cant be right are my perceptions wrong ???????
i would love to get a lot of up votes but its just not happening ?????
obviously this is rather disheartening i will keep posting and try to make some steemit first before investing me hard earned cash
cheers peeps