Joan, you're making this way harder than it is. There used to be a user on ATP who was international and therefore couldn't really "use" the acorns in the not-a-raffles. Therefore, he would give away lots of acorns to people. If the "recent acorns tips" on the front page were posted chronologically, he would have been on there all the time, comprising the whole list.
It works like this. I give User A an acorn for a post I like. It shows up in the recent tip list on the main page. But then, I give another acorn to User B for another post I read. Only my most recent "tip" will show up in the list. It will not show both of my tips given because everyone who gives acorns is only allowed to appear on the list once. Conversely, people who receive acorns tips for one post (or picture or whatever) will appear multiple times if different users tip them. That's why the list will show:
User A gave User B an acorn for picture of Rose
User C gave User B an acorn for picture of Rose
User D gave User B an acorn for picture of Rose
So you can see what's been really popular at receiving acorn tips, but you won't see multiple acorn tips given by the same user, if that makes sense.
