My Time Tracker Chrome extension says these 5 are the top for my past 30 days of browser activity on my personal laptop:

  2d 22h - 9.63% |===================> Discord (friends from an Eve Online corp)
  2d 12h - 8.24% |================>    4chan (mostly the motorcycle thread on /o/ the past few months)
  2d  1h - 6.71% |=============>       Google
  1d 10h - 4.75% |==========>          Hacker News
  1d  7h - 4.34% |=========>           Google Music (last.fm has 522 plays total, 17/day avg over past 30 days)