I'm getting a few broad categories:

  Weather
  Golf
  Basketball
  Celebrity gossip
  TV show

It would be interesting to see what HN readers are searching. Rather, it would be interesting to segment further into what a specific region / group is searching.

Edit: I was just searching for Markdown on Hacker News[1]

https://news.ycombinator.com/formatdoc

Really? For me it was the Pirate Bay and Kate Upton.

I was just randomly clicking the searches to see what could possibly be so interesting about them... turns out it was just a bunch of people wearing clothes... and given the internet, I find that quite difficult to believe.

I don't have any evidence to support this, but I can't believe they wouldn't have any filters in place to weed out all the nasty stuff people are googling.