I think it forces the search to hacker news

On google you'd type this for the same behavior:

  site:news.ycombinator.com google skews

Except you don't need to, you can just type "hn" because google knows hn means you want the hacker news website results

Duck duck go could provide the same behavior if they displayed the top search result of "!<first word> search" when I type "<first word> search" if it realizes <first word> is one of these popular keywords or a synonym