Just a thought -- currently each person gets only one ad on the front page, one appearance in the ideas list, and it's only their most recent Idea, I think. That's because people were creating, like, 5 or 10 at a time, and they'd all flood the list. So now we see just one - which is great, but also bad since our old ideas never get shown and new ideas wipe out the old ones!
Instead of picking just the latest ad for a character, can we show a single random ad of theirs? So on the RP Ideas list, or the Ads list, it's less that each idea has a slot, but each character has a slot - and a random ad fills that slot, and if I visit again later a different ad will be there in their slot.
That way there's a point to having 3 different ads - people will see them! Just not all at once sequentially in the list. And I can create a bunch advertising the various different situations I'm interested in (not just one), and people will see different situations over time, and maybe one will catch someone's eyes. (This also means I can have as many ads as I want, and I'll have to choose myself between having a small number of ads that show up reliably, or a large number of ads with a lot of variance.)