On letting algorithms decide what one sees and can find

How do you choose whose interests the algorithm serves? Sites like Facebook and Twitter can get more ad revenue if you spend more time on-site arguing with your political opposites, so their algorithms seem to increase the amount of "those other guys" that you see.

How do you opt in to algorithmic manipulation when you want it, but opt back out when you want to do your own filtering?

How do you select among multiple items that are equivalent?

One time, after I'd been working out of state for a year, I started watching a certain YouTube video as my celebration song. I probably watched / listened to that same video five to twenty times per day for a period of months. The next time I was nearing the one-year point, I searched for the same video and all I could find was one where someone edited it to repeat some parts a few times and double the length of the song. The one I had originally been watching was buried or even absent from YouTube's search results.