You can easily:
- find out which comments are new and which you have already seen
- scroll to next new comment and it will be marked as read
Click on the next/<number> label.
- manually mark a comment as read to avoid scrolling to it again
Click on [ read ] in top right corner.
- mark all comments as read simply by reloading of the page
If you see after
| <number> comments:
| new 8 then there are new 8 comment since your last visiting of the page| no new comments then there are no new comments since your last visiting of the page- nothing then you have not visited this page yet
| new -2 then you are faster then Hacker News servers because they are still showing old number of comments on the main page
