Like any existing market, nothing explicitly prevents a rich person from artificially inflating a listing they like.
But on Ideamarket, no amount of money can artificially reduce the ranking of a listing they don’t like.
This is because Rank depends on each token’s circulating supply. A short-seller would need to borrow tokens in order to short-sell them, and borrowing them would require minting them — increasing the circulating supply. Thus, short-selling is impossible.
Ideamarket is superior to typical markets in this way.