yeah, but i get the impression history is retained and utilized. If i watch 2-3 how-to videos i start getting how-to videos that are similar to my history, not just random how-to. then if i switch to skateboarding, i get skateboarding videos similar to my history.

This seems like a good algorithm to me, as when i'm watching skateboard videos with my friends, I don't want "how to caulk tile joints" to show up