I am so out of the loop that, when I started seeing mentions of "the ao3 algorithm", I thought it was a sort of joke people made to explain why their fic got buried in the tag/got few readers/etc. XD But seriously, it's super weird! What you see (or don't see) on Ao3 depends on so many things: tags, filters, the size of the fandom, the hour the fic was posted, user scripts like ao3 saviour, etc. ... and these are tools that still let the user have some control, so definitely not the same as an algorithm that shows you what it *thinks* you'll like/tries to sell you something!

Also: thanks to you, I've got "Cracklin' Rosie" stuck in my head now! Play it now, play it now, play it now my BA-BY! XD