I have had a couple decent sized payouts that came after the initial payout, and be much larger than the first. On each occasion it was a nice gift from a whale. It's always a delightful surprise when this happens after I've pretty much resigned myself to the fact that a post didn't get as much attention as I would have liked.

I find there's so much new stuff to always read in my feed, and way more of it than I have time to look at, that I just don't get to older posts as much. It's not a conscious decision on my part to optimize curation, it's just that I look at and vote for whatever interesting content I happen to see first, and that ends up being the newer posts. Occasionally I do find and vote on something past the initial payout period, usually as a result of clicking on a linked article embedded in a comment or something. Having a "related posts" or "people who read this also read these other posts" at the bottom would go a long way toward raising the visibility of older posts.