Huh? "Explore" means to show the user new content. "Exploit" is to show more of the same content. You can say the HN algorithm does both as well: the front page shows a variety of topics allowing you to explore but the upvotes "exploit" shared interest by bumping it higher in page rankings.
Fundamentally content discovery is always an explore-exploit loop. What you tune the loop with is what makes it useful for any given purpose.