Well I translated part of the FAQ to my native language but Im not sure that algorithm is still in use but here it goes, I am paraphrasing because I dont remember exactly:
The first 30 minutes are crucial for curating. If you upvote a post in that 30 minute window then your curation rewards won´t be as big as if you upvote it after those 30 minutes. If the post goes viral and you gave the upvote after the 30 minute window then a big % of the curatino reward will go to you.
If the post goes viral but you upvoted it 1 minute after it got posted then you wont get rewards. If the post is already viral when you upvote it, you wont get any curation rewards.
Thanks, Im glad you liked the post!